Was reading an old article on this, thought worth mentioning here since many guillible people are victims to such "friends".
What are poisonous friends?
IMHO, first of, you think they are "friends".
You trust them.
You give them a benefit of a doubt.
You share secrets with them.
You think they'll cover your back.
How wrong you are... hence the term "poisonous".
Instead, you get hurt.
You get laughed at.
You find yourself in the latest gossip (which you never heard before) or could only be 10% correct and 90% fabricated. (what is a gossip without some pepper and sauce, right?)
Basically, a friend is supposed to support you and occasionally tell you the hard painful truth about yourself. But never ever should she/he always pull you down and make you feel bad.. or even make you into a roadkill!!
The articles further classifies 8 deadly types of Poisonous Friends:
1. The Smilling Stabber
From the description, imagine the person smiling at you, agreeing with you. Then when you turn, her smile becomes a frown and she bitches about you. Nuff said.
2. The Gossip
The friend shares her gossips with you but she digs out gossip from you too, albeit reluctantly or willingly. Beware, you might be known as the gossiper instead!!
3. The Control Freak
This friend likes to control your life: she answers for you, she arranges thing for you and there is no sense of boundary. I had a roommate like that, and boy, when I finally realised it, it was a wee bit too late, and you know how vicious girls get when you break their rules..
4. The Taker
She's the friend who insists you drop everything for her but when it comes to your turn, she's never there. You'll feel like a victim of a vampire with your blood all suck out dry....
5. The "Poor Me" Friend
This friend is whinning and makes you feel guilty for having your own life. Even when you take time for her, she might make it sounds worse as if you're not sincere.
6. The "Poor You" Friend
I think this kind of friend invites you out at the last minute or perhaps invite you out of pity.
7. The "Twin"
She expects you to feel the same and drags you into her world. When she quarrels with someone, she expects you to be on her side. Like the phrase, you're supposed to be her "twin". Personally, I feel like it's also a kind of control freak.
8. "The "As a Favour" Friend
This kind of "friend" is not that obvious because they normally worm their way up into your lives and before you know it, suddenly you feel guily if they ask you a big favour which in normal circumstances you will say "no", such as: "I'm having some financial difficulties. Can you help me out with a loan?" etc.
In short, whenever the friendship seems to be exhausting you till you look like this:
Be realistic, cut ties with the so-called-friend and move on. It's your life and you will always meet more potential-friends out there. Just be careful...