This one was making the rounds on Facebook recently. I love it. Seriously. I'm all for questioning authority, thinking for yourself, and exploring on your own. I am the first to encourage students to go off and learn for themselves.
There is a time and place for doing this. You can't start every training process already being a skeptic. You can't assume your coach is wrong until you've tried out what he's telling you.
Every now and then, we'd get someone coming through Sityodtong or a PDR course who would, within five to ten minutes of starting, would argue with the trainers about how we were teaching. Sometimes, they had prior experience. Sometimes they were just idiots. Either way, it didn't make much sense. Guys who had never fought were telling coaches who had produced professional fighters that they didn't agree with the coach...
If you've put a substantive amount of time into training with someone, or in a particular system, then start questioning it. But first...just listen. The results might surprise you.