I have trouble with this as well. I tend to be the girl who is “too nice” and I don’t tell people what I really want or what I really feel until its too late and we’re fighting. I’ve nearly ruined a lot of friendships that way. Now whenever someone asks me to do something I don’t want to do my usual response is, “I’m sorry, but I’d really rather not” or “I can’t because…” or “I really don’t think that’s my thing, but I hope I haven’t offended you.” For close friends I usually say, “Sweetie, I love you but I really can’t do that” or “You are my best friend and I would love to, but I won’t be able to make it” or whatever. Also realizing what my boundaries are helps me. I used to get into situations by being persuaded into thinking nothing bad would happen, and I ended up making stupid mistakes. I recently had to tell a friend of mine that I didn’t want to have dinner at her house, and I was just honest with her and I said, “Normally I would, but I wanted to spend time with my husband tonight” and she totally understood. Most of the time your friends will understand.

Honesty is the best way to get people on your side. Most people can tell if you are making up something to get out of a situation and it will come back to bite you. If you don’t want to then you don’t want to. Don’t feel the need to apologize. Its not you, its them. Don’t feel guilty about having your own thoughts and feelings.

If someone is being an ass to you, then tell them so. “I don’t like the way you are treating me. If you don’t like me then leave me alone.” Is pretty straightforward. Don’t be afraid to tell people how you really feel. Chances are the people who are treating you unfairly might not even know they are doing it, or they are jealous of you and are just dong everything they can to bring you down.

It’s not clear who your having a problem with, but I want you to go to the book store and pick up a book called… “Emotional Black Mail”, by Susan Forward. It cut’s through the confusion people create in their quest to hurt and manipulate you. Trust me, you won’t be sorry you bought it!
Good luck, but remember…

Some people are like Slinkies….
Not really good for anything,
but they still bring a smile to your face……...
when you push them down a flight of stairs…..
and
“A heart bent on it’s own way will always find justification for it’s rebellion, no matter the evidence”
Mark A. Olsen