Normally our pattern is dictated by the wind direction which is easy to tell with a wind sock right next to the pilots. There are, on occasion, some pilots who can't either tell what direction the wind is blowing even though it's blowing right in their face, and have to takeoff-land downwind since they can't fly a right hand pattern. I'm waiting to see a ground collision from planes landing or taking off in opposite directions one of these days.

Hogflyer