Over time, I've compiled a quite heavy list of pointless UI restrictions that, in my opinion, make no sense whatsoever and need to disappear.
  • Sorting or manually reorganising the inventory while in "crafting stance" (not during actual crafting, but when browsing the recipe list) can't be done.
  • Not being able to (un)equip gear or weapon/tool while in a conversation. Eg. where you know you'll have to hand over something that you're wearing, but forgot about it and initiated the conversation with the NPC first.
  • Return and teleport can now be used while mounted, even mid-air - but we still can't use those commands while /sitting...
  • Hunt mark bills can't be opened while /sitting, even though we can check them, for example, while in a dungeon...
  • Zodiac glass also can't be used while /sitting or while mounted...
  • No item can be purchased off the MB, or put up for sale or entrusted to retainers if the DF queue pops while interacting with those, having to cancel everything and remember to do it after the duty.
  • Not really UI but since it's so restrictive: dropping off platforms that do have ground beneath them - I don't have a list, but there are quite a few such, and it's mind-boggling. Also, random spots in HW zones where we can land vs those where we can't... it's quite insane.

I could add "why???" or "can't see the reason" to basically each and every one of these - so instead I just put that here.

Please do add your own if you have any.