People wash out at my company for:

1. Failing tests in ground school.

2. Not knowing callouts or being able to fly sim. Know your callouts and do a lot of chair flying in front of the mock up.

3. Not being able to line up and adjust altitude and speed properly on a visual approach during IOE. And visuals are what we get 90% of the time and several of them aren't easy, like the River Visual, Circle-to-Land 33 in DCA, Expressway Visual at LGA, etc. So it's kind of a big deal.

4. Whining.