Yes if it hurt someone and if it's unintentional on my part. Of course it works and I feel great.
I don't apologize if I think they were in the wrong to begin with and if I think I would be justified in doing it again. I have before but then I took it back, because I can't live a lie or lead someone on.
I probably have apologized to certain friends when I don't think I should have to keep the peace, but slowly distanced myself from them if I knew we'd keep having the same issue.