Rules you learned from playing

So after playing 3000+ hours i have learned some rules the game has. 1) Golden coin has a 75% chance to disappear if you are at 13 coins 2) In depths/necropolis 2 if you have more than 30 coins the shop is almost guaranteed a greed fight and if not the restock machine has 80% less chance of appearing. 3) After maxing tear rate you have 30% more chance to find not flat tears up items

Write rules you learned from your experience down in comments