I'm one of those people who is continuously cracking myself up simply by thinking about things that have made me laugh before. Homer Simpson quotes are pretty notorious for that. Once I get started playing his antics in my head, I can sit and laugh for a good ten minutes. Because the thing is, in my opinion a good joke gets funnier with repetition.
When used properly, repetition is a good tool for creating many different effects. In a good horror story, it can be used to create suspense and ultimately surprise. Repetition of actions or dialogue between characters can strengthen the bond in their relationship. And repetition in the sense of a running joke can create some great comedy. Think of Michael Scott's hatred of Toby on The Office or the broken step in Modern Family, or every character except George Michael's reaction to Ann on Arrested Development. It's the same joke over and over, but somehow it's funnier each time.
So let me repeat, when used properly, repetition is a good. (Don't look for me to repeat this post tomorrow.)