DM and Player of Pathfinder 1E, 2E and Starfinder. Rules-nerd and amateur game designer.

Did you know that in Pathfinder 1E:

• If you aren't humanoid, you don't take a penalty on grapple checks when you don't have 2 hands free?
• A particular triggering event can only grant a single attack of opportunity, but that a character with Greater Trip and Vicious Stomp gets two attacks of opportunity when they successfully trip a foe, as a successful trip and an opponent falling prone count as separate triggers?
• That the feint action is not a combat maneuver despite requiring similar prerequisites and being located near the combat maneuvers in the rulebook?
• That there are no rules for how a mount's actions are restricted by being mounted?
• That you can't combine Vital Strike and a charge unless you have the Gorum's Swordsmanship feat, because Vital Strike requires you to use the "attack action" which is different from a melee attack?

Pathfinder rules are weird. Heck, the grappling rules are so unintuitive and complicated that fans have made giant flowcharts to explain them to new players.