The barrista in Starbucks just smiled at me and wrote his number on my Americano with soy milk

I agree with what REMsleep said, this is no big deal. If he wants to go out with you, how else is he supposed to approach you? He didn’t do anything wrong. It seems to me that you should be somewhat flattered, but even if you’re not just forget about it and act like nothing happened and he’ll probably more or less forget about it too. If he [i]continues[/i] to ask you or starts unwanted flirting or whatnot, then maybe warn him first but you can tell his manager on him.