Blinds Steal or be Stolen

I often find myself at 6 max tables, either 3/6 or 5/10. I am more successful at 5/10 than 3/6 but I attribute this to aggression factors. I play a pretty good game at this level but have some very basic questions...
I generally play very aggressive and loosen up a little at my 6 max tables.
What do you do in these situations...

At a 6 max table should you...