Losing the edge in a game after taking a break

[Mojo]

Let's just say I'm curious. I've just had a quick cheeky trip to France, about 10 days. After said break I just tried playing Team Fortress 2 and I'm playing awful: My aim is off with rockets, I can no longer do any acrobatic spy maneuvres and I only just manage to break even K/D wise after each match.
However, I boot up ye olde classic Battlefield 1943 on Xbox Live Arcade after about 4 months and I'm on top form.

I find it incredibly confusing as to why Team Fortress 2 is so painful to get back into, but I can jump on BF1943 after a much longer break and continue like nothing happened. They are both twitch response based. TF2 used Mouse/KB and 1943 uses pad but apart from that...

I guess my question is... what do you think makes a game easy/hard to get back into after a break?

 

[Mojo]

Maybe you're just playing against better players than usual and then frustration is getting to you?

10 days doesn't seem like a long enough time to irrevocably diminish however well you were playing.

That's the issue, I wasn't playing players that are better than I'm used to, but my aim was all over the place =( just hitting enemies with rockets was hard, it was like my mouse sensitivity had turned up even though nothing had changed since before I left