LEGO & Horses are so different
LEGO is hard-edged, plastic, and clean. Horses are furry, animate, and dusty. Although if you ever handle LEGO that has been used in a freeplay area, you will feel an overwhelming need to soak your hands in bleach.
LEGO stays were you put it. Horses only do so if they feel like it. Unless, of course, the cats get into the bricks.
LEGO skills are progressive. No need to rebuild easy sets or simple MOCs. Even upper-level riders need to warm up, practice 20-meter circles, and work on a decent halt.
LEGO & Horses aren’t so different
Both are seated. I had an attack that we think was shingles on my posterior. Sitting anywhere on anything was problematic. Also biking. Amazing how many of my activities involved my tailbone.
Neither are on the computer. Work life, social life, entertainment. Boy, do I get tired of staring at a screen.
Both attract avid Fans who will happily chat on the chosen subject for hours.
How do your hobbies compare/contrast?
Virtual Brush Box 
Ballroom dance partner: I don’t have to wash him, clean his tack, muck out his room or braid his hair to get ready for a show. Don’t even have to brush his teeth! On the other hand, horses don’t talk back, are in their stalls when you’re looking for them (hopefully) and get quietly in the trailer when you ask them to load.
I think the key is hanging out with other people who love what you do. Knitting is a solitary activity, but, I belong to a knitting group. So we can hang out and talk about our knitting. And maybe other stuff, too. For me, having horses at a boarding barn was a huge part of my social life.