We are a tribal species. Study after study has shown that humans who are isolated from other humans tend to decline rapidly, up to and including shortened lives. This is true for human beings of all ages, from small children to the elderly. Other studies show that, whenever we are put into groups, even with total strangers, the vast majority of us will automatically start to cooperate with each other, as well as the fact that our brains light up with reward chemicals when we help other people. We don't just like having a tribe of people around us, we come preprogrammed to NEED a tribe.

So, yes, we need friends, but we aren't always that good at BEING friends. Children develop highly evolved and complex friendships because, at a young age, we still have so much to learn about human interaction. Plus, being free from having to support ourselves, we have the time and energy to devote to developing complex tribes. As adults, we lose a lot of these skills because ordinary life's demands require most of our attention and energy. So, here is a list of things that adults commonly do that make them terrible friends to other people:

5. Emotional Competition

Every one of us has one of THOSE days occasionally. Everything seems to go wrong, to the point that even the slightest little thing adds to your general sense of irritability. You're stressed out, overwhelmed, and you're not sure whether to go off like a maniac at the next person who crosses you or lay down in a darkened room and weep. Invariably, someone whom you consider to be a friend will ask you about your day and, because they are a friend, you'll open up and tell them what a crappy day you've had.

Just as invariably, the terrible friend will immediately try to one-up your crappy day by telling you how much crappier their day was compared to yours.

Why it's terrible: When a friend is having a rough time and you one-up them, what you are saying is: "You came to me for sympathy and I have not only deemed you unworthy of my sympathy, but you should feel guilty for not giving ME sympathy."

This is not a "misery loves company" move in which your friend is trying to make you feel better by commiserating with you. If so, your friend would have acknowledged your pain and said something along the lines of "Those bastards! I know exactly how you feel."

What SHOULD a good friend say instead?: "Hey, it sounds like you've having a rough time. Is there anything I can do?"

4. Emotional Leeching

This is the exact opposite of emotional competition. An emotional leech is a person who discovers that they have good friends who will be sympathetic to them everytime they have a bad experience. That's what good friends do. But the emotional leech preys on his/her friends by using bad experiences (real, imagined or exaggerated) to get and keep attention focused on them. This is the person who's ALWAYS complaining about some difficulty they are having. Every day, something goes wrong at work or their kid is sick or their car broke down or some relative did something awful to them. Every word out of the leech's mouth is a demand for attention and sympathy.

Why it's terrible: Being an emotional leech sucks the happiness out of the leech's friends. Having a friend who is perpetually bad off not only takes up your time and energy, but it makes you feel guilty about things NOT going wrong for you. You can't enjoy your life or be happy because that would be like gloating in front of someone worse off than you.

What SHOULD a good friend say instead?: How can you tell the difference between a real friend who's just having a run of bad luck and an emotional leech? When you help a real friend, he/she usually says something along the lines of: "I really appreciate you being there for me and someday I'd like to return the favor."

3. Cancerous Planning

Cancer occurs when a malignant cell goes nuts and takes over your body's resources, slowly sucking the life out of you. A cancerous planner is a friend who takes any plans you've made and sucks the life out of them until they are no longer your plans at all.

Here's an example: you decide to invite some friends over to watch the big game. The game is on Sunday, so you plan to get some beer, maybe order a pizza or two and just have a good time. Then, that one friend calls/emails/FB messages the group and says that he/she can't be there on Sunday, but gee, he/she really wants to see everyone, so couldn't you guys just all get together on Saturday instead? Instead of watching the game, maybe you guys could get a movie or something... as long as everyone gets to hang out. After a few more exchanges, it is no longer going to be hanging out at your place on Sunday with beer and pizza —now it's going to be visiting an art gallery on a different weekend, they're going to need you to drive, and they'll be getting dinner at a fancy restaurant that costs a fortune, and everyone is bringing their kids, so it will be a strictly no-booze event.

Why it's terrible: In the case of the cancerous planner, the world revolves around them. Everyone they know is expected to be subservient to their needs. All attention must be on them.

What SHOULD a real friend do instead?: Call/message/tweet: "Hey guys. Sorry, but I can't make this one. Have a good time and I'll make it up by hosting the next event."

2. Grandstanding

This is the person who wants you to know how awesome his/her life is all of the time. All of their interactions with their friends seem to involve tales and photos from their fabulous vacation, or stories about how great their kids are doing and how many awards they all get. It's not just that this person likes to boast about their own accomplishments: they won't even acknowledge anyone else at all.

Why it's terrible: This person doesn't have or want friends. They just want an audience. If you're friends with this person, then you have no purpose beyond making them feel important by observing them.

What SHOULD a real friend say about his/her accomplishments?: "Things are really going great for me right now. I want to share that with my friends and I hope they will share their accomplishments with me, too."

1. Acceptance Demanding

Social media is essentially flooded with inspirational quotes and self-actualization statements that all carry the same message: "A real friend accepts you for who you are." Awww. That's a sweet sentiment. It also makes you a terrible person if you follow it.

Why it's terrible: Cooperation between two humans is supposed to make both of them better. Friendship is a two-way street in which the value of the friendship is greater than the sum of its two participants. Take even the smallest of things: table manners. When we are alone, we have terrible table manners —hell, half of us don't even bother with the table, preferring to snarf down our mac 'n' cheese on the sofa in front of the TV right out of the pot using the spoon we mixed it with. But, when a friend comes over, we'll immediately improve our manners. At the very least, we'll offer to put the mac 'n' cheese into two bowls and use an actual fork.

On a larger level, two good friends should make each other more empathetic, better at problem solving, and more successful. When a person demands that their friends accept them as they are, with all of their flaws, they are saying: "I have no intention of helping to make you better in any way. I expect you to drag me, like an anchor, weighing you down." It says that, when a friend comes over to your place, they can just sit and watch you snarf down your mac 'n' cheese because you sure as heck ain't gonna be sharing it with them.

What SHOULD a real friend say instead?: "Sure, I have my flaws, but you make me want to do better."

IS THERE A COMMON THEME? Of course! Almost all terrible behaviors can be traced to basic selfishness. In order to be in a true, functioning human tribe, each human has to sacrifice a little of themselves to maintain the group, so that all of its members can reap the rewards. Being in a friendship requires a personal investment. Terrible behaviors almost always occur when one person demands all of the benefits of the interaction, without investing anything of their own.