Critical mass doos and donts?

I've only been on 2 CMs, but I have to say that riding fixed is defo the best way to go, cos' let's face it, if there's one thing fixed is brilliant at, it's riding real slow.

Also, don't go with an attitude, it don't help anyone
Also, do go with a couple or 4 beers though
Also, pick a CM when it isn't raining

I thought it was illegal to ride and drink?
From what people have said and looking at some vids of cm i think going without an attitude is the best advise.