If you happen to know a girl named Crystal there is one pick up line that you may be tempted to used but I gurantee that it is one of the stupidest things you could ever say. When the girl walks into the room you say now that you are here I can see the future.

This would mean that you think of her as a crystal ball. That can come off as something very mean to the girl. I also think that saying it makes the man sound stupid. It is even stupider if the girl spells her name with a k instead of a c.