Urbs, how about this example...
You know I live in Ireland now & all. A while ago I played in BBswing, just a friendly game.
I stood at the upper left of the level.. being able to look very far right. Hiding, sorta. Just being idle.

I saw a bullet in the UTTER FAR RIGHT OF THE SCREEN and the next thing I get hit. Thats some 20 tiles you're talking about.
Is it any wonder I complain about lag if that happens???

And that does happen quite often actually. Random packet loss or so.