You can play normally in FPS because it doesn't checks your position every milisecond like in FOnline, that's why if you have, for example, ping 500, you won't move faster than 1 hex in 0.5 seconds, if your ping is 5k, then you'll move 1 hex every 5 second, you don't see it during non-combat, because it doesn't update for you every time, and you see your character further in move than he really is for everyone else on server, while in combat everytime someone attacks you, it synchronize position with you and you see your real position, sometimes I can see players teleporting on 10-20 hexes, especially if they instantly changing direction of run, it means I got lag and missed some of thier moves.
Try to run somewhere 30 second in a row in one direction (in some big town), then drop some item and start run back in other direction, later, you'll see your character teleported back droping that item if you have high ping, because this is one of actions that forces to check your position and synchronize it.
If you have low ping you won't see much problems.