Are they still using the RNG combat system? been forever since I checked this out.
If you use that system, then your skills start with their cooldowns (some of which are pretty long) when you enter combat. When you are out of combat, your hotbar does not show any combat skills, just harvest skills that you put there. You have to push Z to show the combat hotkeys, who will then first have to come off a cool-down. Same thing when you get aggro from the out of combat state: your hotbar changes to the Combat hotbar that first has to get your skills off their cooldown.
Imagine how annoying that is when some Wolf is already chewing on you, and you have to wait untill you can finally start to unload some skills on the mob yourself. It all feels slow as molasse, you do not feel as if you have any control of the fight, skills hit accordingly to a percentage (that becomes better with skill use) , when your combat bar shows your right/leftclick-to-move suddenly starts auto-shooting arrows instead of moving you around (so you have to switch to wasd movement during combat) and so forth.
I am not even sure if you can change the latter in Options, maybe you can, but the Combat overall is so horrible that I can't even be bothered to go into options.