I've not really gone back to the same places too often, but I can understand it and will probably do more of it in future.
For me, I hate the stress/anxiety of the unknown. Far too many holidays have been spoilt by bad accommodation, poor service, fully booked attractions, disappointing over-hyped attractions etc.
When I find a hotel/apartment that we like and didn't have problems with, in a town we like, and when we find restaurants with good service, etc., we tend to be drawn to go back, just for the peace of mind that it'll be less stressful, we know it, etc.
We've just been on a northern european cruise. I found it stressful for weeks before and right through the cruise. I was anxious about virtually everything as it was our first ever cruise and was "big" for us for a few family reasons. We had high expectations and the planning/organising was on my shoulders.
Once we were back home, I was planning to do it again next year. Same ship, same itinery. There was SO much we missed and a few bad decisions made, simply because we weren't accustomed to cruising. I know I'll actually enjoy it more next time as I won't be as stressed/anxious about every little thing, so will be able to sit back and relax.