The x-mas event caused some extra lag until they updated. Lag usually has to do with how many people are on the server or channel and internet connection. Anytime I get lag it is because my internet connection is bad for a while. My connection is good most of the time and I get almost zero lag even though I live on a farm property with a lame internet service.
So to help fix your lag problem you should make sure your internet is fast and don't download anything while you play. If your internet is slow then check with your internet provider to see if you can make it faster. Playing on empty channels might help if one channel has a lot of players.