That's it. I've been struggling to figure out what I can't stand about iOS and it just clicked. It's the lack of seams. When something breaks I can never figure out what specifically broke, so I can't reason about my mistake (or know who to contact if it's not my mistake).

I like seams so much that I'm running google play services in a sandbox (Graphene OS) so google has to grovel for my permission like everybody else whenever they want to do something. It's a little annoying, but it's teaching me where the seams are.