Why do I play tournament chess games better than I play casual games or team matches?

In tournament chess games, up to now, I've never lost.

In my team chess matches, I've always lost or close to losing.

In my casual games, my win rate is around 50-50 with people of similar rating as mine. 

Why would this be?

Gotta be psychological - when a tourney spot is on the line, sometimes it is easier to get in the zone...

.. juz coz it's a Tourney !!! ... lol

You're probably right. Maybe those instincts hardwired into man (no sexism intended).