All of the above.
I love deep RP, crafting characters, their stories, solving challenges, experiencing other worlds, playing through other experiences, going where I might not be able to go in my everyday world. I love the tactical aspects of games, the puzzles, the "love it when a plan comes together." I love the mechanics, the math, the design beauty therein. I love being creative, I love the acting, I love the collaboration, I love the camaraderie, I love the life-long stories created, and all the fun of hanging out with friends aligned together towards active engagement.
RPGs do not just tickle one part of my brain / only scratch one itch -- that they encompass so many different aspects is what has me delight in this hobby for 40 years.