Magic's infinite combos are fun to dream up and often even more fun to pull off in a game, but building a combo deck is sort of like writing a program that makes your computer crash; the fact that you can do it proves that you have a certain degree of skill, but it isn't really the most constructive way to use that skill. Combo decks ruin the fantasy of Magic, and there only way to keep them from doing so is to arbitrarily introduce a rule preventing them from going off, such as a prohibition against repeating a game state.
I noticed that I felt this way more than two years ago, and I still do. I'm a little Johnny but a lot Vorthos, and it's rare I can satisfy the first without annoying the second. So while I don't generally invoke that rule, I'm always saddened when I see a game end in some silly combo instead of playing out in a fashion I could believe might actually happen.