This topic surfaces on occasion and it's not unusual for Belichick's name to come up in this context. But it always brings to my mind the story Tony Gonzalez told about the year when Belichick coached him in the Pro-Bowl.
According to Gonzalez, Belichick was extremely demanding. In fact, he never caught Gonzalez doing anything right all week ... he always found something to criticize. If it wasn't his cuts, it was his blocking. If it wasn't his blocking, it was his start off the line. That sort of thing.
Anyhow, due to the fact that Belichick's standards were, apparently, impossible for Gonzalez to meet, he tried even harder at practice to get it right. Then, on a particular play in the game, Gonzalez ran his route, caught the ball properly, and gained some YAC and a first down. Afterwards, he rotated out and came to the sideline fully expecting Belichick to either criticize him again or ignore him completely. Instead, as Gonzalez walked by the coach, Belichick (without even looking at him) said, "Good catch, 88."
Gonzalez said that one, small compliment shocked and surprised him. And, after all the problems, it made him want to bust his ass on the next series even more. And that's in the Pro-Bowl where nobody really cares ... supposedly.
Obviously, the moral of the story is that (even though many coaches do) you don't have to constantly scream and yell in order to be a hard-ass. And if you're good at it, you can motivate players beyond their own expectations. Of course, even though Belichick has had his share of player, coaching, and official confrontations as well as the occasional melt-down, he's generally perceived as stoic ... almost aloof ... but he isn't a "softie" by any means, either. To me, he sounds like a guy who has figured out how to identify a player's personal button locations and knows when and how to push them.