i think guys would be freaked out if a girl looked totally different without makeup, but a little makeup is to be expected. if I was a guy I'd rather a girl wear makeup and try to look the best she can than go around with a plain face all the time. I know guys who feel that way too
I think that guys feel like that if they have a girlfriend who uses so much makeup she could plaster it on with a spackle knife. But I think if they have a girl who keeps it simple and tries to make it more natural looking then they don't mind it and maybe even like it.