Rufus is sneaky, he refuses to play against certain things until you stop using them. Then he kills you with ghost councils and rancors until you cry.
I seem to be pretty rubbish at constructed stuff. I have had way better luck with sealed. Maybe I'm more lucky at that, or maybe it just suits my style more. I dunno.
I've done alright in the pauper we have played too, but my lack of knowledge of cards from the ages hurts me sometimes.
In standard I have a pretty horrendous win/loss ratio I think. Partially it could be because I find it so hard to resist a theme and like to try out different things just for variety rather than stick to tried and trusted cards. My landkill deck was a somewhat horrifying example of that!