There are plenty of clowns who call themselves instructors. You can recognise them by their shouting. When they shout, you should stop the lesson and that means you don't pay from that point on. When on the ground, you explain to them in simple ways what you don't like about their instructional technique. I find holding their lapel with my left hand often gets my message across.
We should also differentiate between strict and high standards. I was taught many years ago at Bristol (Martin Barnes's lot). They had, and still probably do have very high standards, but they didn't shout. Strict implies no compromise, which is unrealistic if you apply it to people. High suggests that you will be helped and taught to be as good as you possibly can be.
As for quoted hours, it all depends. A minimum is just that and overshoots regularly occur, even for qualified pilots under going type rating courses. We all learn at different rates and every now and again we find a section that is very challenging. And if I think back, I remember I wasn't happy in twin until I had about five hours on type. Then all I had to do was learn to fly the thing on one engine, which does appear to be a bit of a waste of an engine. We must also remember that piston twin is probably the most complicated thing you'll ever learn to fly.
Regarding the screaming and shouting, it is just not on. There is also no benefit in putting anybody under pressure by shouting. That is not part of instruction. Choosing an inopportune moment for a failure is a reasonable thing to do, but then only towards the back end of the course. And that is after the pupil has been prepared for the challenge and has been briefed, prepared and practiced beforehand. Every day, we all make errors and forget things - it's what people do. A proper instructor will mention immediately critical items or will take over control and explain what went wrong and provide a fix or allow you to perform a mental reset. Minor items will either be discussed on the ground during the debrief or be ignored. But the debrief must also cover progress, something too many instructors omit. And let's face it, if you are not making progress, why bother continuing? You must change instructor.
Lastly, what goes around comes around. In my company we have a former instructor who used to make people's lives a misery. But he is an F/O and they are now captains. His former pupils are now making his life a misery. He is "Billy no-mates" and his life must be hell as they are demonstrating the same degree of intolerance that he did.