"Typical behavior for a woman!"
"Men always act that way!"
Ever heard those? You probably have.
They may be delivered in anger, or, weirdly, as an attempt at reassurance..."I don't like the way you're acting but I know you can't help it because of your gender."
Which can be comforting, I suppose. Anyone? Have you found it comforting?
What stereotyping does is close a lid. Once you throw the weight of sociological knowledge (everyone knows that) behind your argument, the door's closed, and you no longer have to listen - or to look at your own behavior, to see if what you don';t like...
...is a reflection of you.
What's interesting is how acceptable gender stereotyping in marriage is to the user. People who would never stereotype a neighbor or co-worker by race will happily toss their spouse into the blender, and turn it up to frappe.
It's also a relative of "you always do that". That's one of the worst things you can say in a relationship, because it's not true, and it demands an almost impossible on-the-spot refutation.
So, guys...today's suggestion is please don't generalize about your mate.
You married a specific person whom you loved, and hopefully still love.
Don't deny him or her their uniqueness.