I was always more worried when they quit yelling.
I'll never forget in high school after a particularly bad half of basketball our coach coming in and very calmly singling out myself and another guy and saying "I've been involved with basketball for a very long time and you two may have played the worst half of basketball I've ever seen anyone play." That one stung a bit.
We had a similar rant at halftime our first 7th Grade basketball game, except is was all 15 players. I could write a novel, but it took about another week of practice before most of the 12 year-olds on the team realized that just because a guy is your basketball coach doesn't mean they know much about basketball.