Is it normal woman have bun hairstyle in work ?

It depends what sort of work she does: anything physical will make her hair untidy very fast unless she's sprayed it stiff beforehand.

Is that all you have to worry about?

Her hair gets messed up at work...

Why is she working but you aren't? I wish I had a woman like that, man you've got it maid

Is this is serious question?

I'm at work and have my hair in a bun. When I come in to work with my hair down it'll end up in a bun in a just a few hours. Why are you worried? You should be happy she "lays her hair beautifully" when you pick her up, she's probably looking good for you and you are making up an issue in your head.

Yeah, almost every girl does that.. you leave the house looking great and come back looking like a tramp. Perfectly normal.

There's a girl at my work who wears it in a messy bun and I think it looks hot. What's wrong with a bun?

Hair spray.