vinney on Nostr: You take the action, the client processes it a bit locally, sends it out it to ...

You take the action, the client processes it a bit locally, sends it out it to relays, the relays process it a bit, save it to a database, send out responses over a bunch of websockets, the clients receive those responses, process them a bit, update some local state, update the UI.
It's incredible that it's even as fast as it is!
A little network lag or inefficiency in code, disk write speed, etc. in any of those steps.. it adds up.
Any user-facing client (of any software) that feels nearly instant is either a piece of an entire extremely performant stack, or its tricking you a little bit and handwaving over some of the laggy work.