I very rarely hold grudges, I can get very irked with people at times, but life's too short, people are less than perfect -especially me, so I don't believe I have the right to hold a grudge against anyone, not for any great length of time anyway.
Sometimes I bump into someone I know I had beef with some time ago, but when it gets to the point where I cant even remember what it was - I think, what's the point in trying to remember. I expect to be treated the same and it puzzles me when It often doesn't work that way.