One of my previous instructors talked about another student. He was on to 35 hrs and still hadn't mastered the flare. The instructor had a sit down with him and said that perhaps flying wasn't for him and that he didn't want to take any further money from him as it was wasted.
I find that attitude a little worrying. I would have suggested he fly with someone else, as different people can respond to different methods of teaching. It's not uncommon to stick at a particular point, and sometimes a fresh approach or way of teaching can cut through that. I know of THREE instructors who were told at some point in their early training that they'd never make it!
Luckily they didn't listen.