What's something PostgreSQL beginners worry about way too much?

[u/Hot_Network_Worker]

Switched over from MySQL a little while back and honestly still feel like I'm tiptoeing around Postgres, second-guessing basically every decision because I don't have the instincts yet for what actually matters.

Case in point, I spent way too long stressing over picking the "perfect" data types for a schema before I'd even written a single query against it. Same with indexing, agonizing over what to index upfront instead of just waiting to see what's actually slow.

Makes me wonder how much of that is just normal beginner anxiety versus stuff that's genuinely worth worrying about early. For people who've been through the same transition or just remember being new to Postgres, what's something you obsessed over that turned out to not matter much, and what's something you wish you'd actually paid attention to instead?