I wanted to revisit a very old question of mine, asked when I was relatively new to math.se., if nothing else, to remind myself why I participate here (and why I returned after a very long sabbatical from math.se). Two points:

$(1)$ I participate and returned because I learn a lot here (or rather, math.se): about math from other users, about common "stumbling blocks" encountered by students, and about what helps people learn and come to understand concepts with which they are struggling.

$(2)$ I participate and returned because I savor those precious, albeit sometimes rare, moments when those posting questions experience an "Aha!!!" moment.

Just thought I'd share.

Cheers!