Congratulations. You now understand why the GCD is 2.5 seconds, and there is such a long telegraph for boss fights.

Since you can play on servers on the other side of the world, there will always be this slight delay. Since not everyone plays on a PC, and the networks we connect through vary in quality, there will always be this slight delay. It's built into the very nature of the Internet.

You don't notice this as much on other games because you're almost never playing on servers outside your local country, where the latency is more consistent between players.