When I had persistent issues with lag that lasted for weeks I ended up learning how to use Windows traceroute and ended up learning how to identify that the problem was with the last server hop or so - which I ended up learning was PWE server territory so there was nothing I could do but complain or play something else.
Then came the patch to fix the emote spamming crashing MC thing and I've had a pretty reliable connection since.
*tosses another digital goat to the pile*
Hope your lag goes soon! Sucks, I know.
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Oh hey, I can't get past the authentication server right now.