What I mean by favorite here is
"what I often find myself greatly admiring when I notice it's done really well"
gonna go with Director of Photography (cinematographer). with emphasis on the photography.
Some things I've watched recently that illustrate this role.
- Saltburn, great use of vertical space with the 4:3 aspect ratio, lots of color and natural light. Summer is captured well.
- Crash (1996), Lots of night scenes (always tough to get right), the setting looks appropriately dark, grimy, and mechanical.
- Fight Club, also a (literally) dark film and looks great.
I’m a day late, but my choice fits that: cast driver. Get the actor to work on time and you can sleep or read theory all day.
Edit: my answer is dumb if you’re watching the movie, but if you have to work on the crew, it’s nice work.
Non-dumb answer is either cinematography or sound.