Luella, you always have the right thing to say! I think I need to go back and read all of your posts, LOL.
I steer clear of nasty people too but sometimes there are situations where you can't escape ie family gatherings, in line at the grocery store and people that are usually nice will say things that you just don't know where they came from. Assertiveness is one thing but downright plain bitchy for the sake of being bitchy is another.
You are correct though, I do have low self esteem and try too hard to please people but I am in the process of working on that. I learned that caring what others think stems from caring what my mother thinks of me and I could never get any recognition from her no matter what I ever tried to do or have done. I have learned that I can't create relationships with others that will give me what my mother did not. However, putting this into action is not easy. I am still new at it and move 3 steps forward and 2 back. Right now I have fallen back and need to do more work.