Have you ever won over your enemies with kindness?

I'm not religious but I think Romans 12:21 is a wise part of the Bible: "Be not overcome of evil, but overcome evil with good." or it seems to come about by the phrase "Overcome your enemies with kindness."

It's good as advice in general - to not give in to hate and cause suffering to people who wrong you, to control your emotions and make people see your positive side ... but is it actually practical in the world today? Has it ever worked for you?

I'm not referring so much as to people who I get off to a bad start with then make up by being friendly (I'm sure we've all had people like that at places like school), but situations where someone goes from being considered unliked or is seen a rival but to fully hated.

I've had situations where people take advantage of me, so why would I let them continue to do so?

Or one of the most bitter times was being harassed at a work place through some petty HR procedures. I resisted getting really angry and ranting in person or by email, eventually choosing to resign and move on with my life as the job was going nowhere anyway (though I did compile a lengthy HR report for senior management ;-).

I could have done so much petty stuff but I resisted, nor did I do anything nice to try and win them over - after all, why would I after being treated like that? What would be the point?

I think a balanced view of trying to understand why people act in a certain way, to try and overcome the problems and help them if they're receptive, but not to let them walk all over you, is the best course of action. What do you think?