It's not strange, I think people question values/purposes/meaning when things don't go the way they expect them to go, so they do an internal "check" so to say, but I don't even think that's the majority of them. I just become nihilistic when I'm depressed; most others I know just whine and sob and blame everything on their incompetence. And then there's a few people who are able to accept life at face-value and accept changes as they come, probably like you, who don't get depressed over things not meeting expectations.
Or something. :/