I don't play 'good' or 'evil'. I play a character with motivations and desires, and I act on trying to fulfill them. If other people in the game world decide that my motivations and desires are 'good' or 'evil'... that's their call, not mine.
That being said... I am also quite cognizant (out of character) of making sure my character's motivations and desires fit within the motivations and desires of the party as well. If they don't... then I (as player) change them or don't play that character at that time. But if it turns out that my motivations and desires are congruent with the party's (except my actions are considered 'evil' by others, even if the party's are not), then so be it. It's an interesting dramatic situation that we as a group get to roleplay around.
That being said... I am also quite cognizant (out of character) of making sure my character's motivations and desires fit within the motivations and desires of the party as well. If they don't... then I (as player) change them or don't play that character at that time. But if it turns out that my motivations and desires are congruent with the party's (except my actions are considered 'evil' by others, even if the party's are not), then so be it. It's an interesting dramatic situation that we as a group get to roleplay around.