I'm gonna have to give a couple of things because it's too hard to just pick one:

1. People being genuinely into their hobby. That just shows up on their face and makes them 1000% more interesting to just watch and listen, whether I care about that thing myself or not at all

2. When I find some good band that I haven't heard about before but the vibe they give off is something that reminds me of my childhood or people that I know

3. My plants. Whenever I see a new leaf or branch or anything, it just makes me so happy for it and makes me want to root for it