Latency issue in this game...

[Tigercrane]

This is a design choice, that SE have gone over multiple times - and while I don't agree with it, it's here to stay unfortunately.

All skills, both on and off GCD skills, are applied after the animation (or at least a certain point), and are not applied the moment you hit the button.
This is a design choice from SE's perspective.

And considering some of the really elaborate animations (Dragon Kick Im looking at you), it can be forever until a skill lands because of this. At least truncate some of the animations, SE. It also makes skill speed really useless past a certain point.