I might be weird, but I actually look forward to starting a new job.
Expectations are lower for new hires so they're easier to exceed, for example.
Learning new skills is also fun for me.
It's usually the point where I start getting too familiar to my co-workers that things tend to disintegrate at work. I sometimes wonder if I wouldn't be better off quitting the moment I get a good review from my boss, instead of waiting several months or years later, as good reviews steadily turn to "not a team player", "insubordinate", "does not follow instructions", "unpredictable", and so on.