Yes, I experience such things from time to time. Especially with grief.

My neighbor who was like a grandma to me passed away this Summer. Some weeks ago, a random thought popped into my mind that reminded me of her, and suddenly I almost started to cry. Other times I'm perfectly fine, but sometimes stuff like that happens.

Another example would be my pet rabbits I used to have. They've been gone for years now, but I can still sometimes think of something or see something that reminds me of a situation with them, and I'll be sad.

Of course this also goes for other emotions and circumstances. Sometimes the smallest things can make me mad, or also happy.

I think this is one of the things that most people experience from time to time. I hope that you're not alone in this helps a bit with it.