I can't speak on behalf of every instructor with ATP, but the instructors I had when I went through the program and the instructors who I now share my day with are all helpful and patient.
Realistically speaking, noone can or do expect perfection the first time.
What I personally do expect though is an effort.
If I call you up two weeks before your start date and tell you to know a small blurb on page 32 of our training supplement called 'Power Settings' by the time you show I expect you to make an effort to do this.
If I tell you to go home and study single engine aerodynamics I expect you to do this. Do I expect you to show the next day and be able to spit out flawless facts and definitions? Not at all. I do expect to see a glimmer of recognision in your eyes though when I bring up the acronym 'PAST'.
If you don't, I'll focus and concentrate more on the other students who do apply themselves.
The pressure is far from inhuman. Frankly, I was worried before I started too, for this very reason, but I was positivly surprised.
Up until I started flying I was never a good student, never applied myself (Got a 4 year college degree in Comp. Sci.), but once I started flying and discovered just how much I love it, picking up the books was something I did because I wanted to, not because someone told me to, and that made a huge difference.
Cheers,
Helge