Does it count as revenge if they never realized I had something to do with it?
Now seriously, I rarely choose revenge, if someone wrongs me in any way, something I usually never even let happen I just start to ignore or turn my back on them. But I have to admit, I'm pretty "schemy" when it comes to revenge, the few times I really turned on someone they never figured I orchestrated the thing... good for me.
On the other hand, a simple apology, even if heartfelt never really works. If you've wronged me and are sorry about it, change your attitude, buy me a beer or whisky, explain why the f*** did you wrong me. That would work.