When grading a paper written by someone older than I am, even if it's only a few years older, exclamation points and some of my usual terms of praise suddenly feel like patronization. Especially since this is community college - many, if not most, of my older-than-twenty-five students (and some of the younger ones besides) have jobs and families and are attending school on top of them. I can't even reliably get through three hours' worth of grading in a day.
When I'm talking just about their writing skills, that's one thing. They've come to learn those things, and they need to, as my comma-markings and margin comments about style and organization would suggest. But when they write process papers about ways to learn responsibility, parent a teenager, or solve one of the everyday problems connected to their jobs, they are clearly on their home ground. Obviously there's also a stylistic meaning to the comment, but really, what need have they for my writing, in teacherly fashion, and as though my approval's what makes it so, that they've given good practical advice?