Bookstore Guy

I guess I could have a guy too... Well, I've known bookstore guy for a few years now. A very cute sophisticated type who works at an artsy bookstore right next to where I work. He's a bit on the pale side and younger than me, not the type that I usually go for, but then he's friendly and kind. I usually stop by his bookstore only on occassions, like shopping for X'mas cards or baby shower/birthday/X'mas gift. So we only see each other 2-3 times a year but he remembers me, he asked me where I work and makes small talk. How do you know if someone is interested?

I remember one time I was with my colleague and jokingly I picked up one of the breath mint on the counter right in front of him and I said "'Oral Fixation'? I have that too." And he was beet red. yesterday, I stopped by the bookstore after a year of not seeing him and bought some X'mas cards. (Don't you just love those MoMA cards?) And we kinda exchanged our "same-ole, same-ole"s, he gave me a special giant discount and I really wanted to ask him out. But what if I'm reading too much into it? What if he's not gay? What if he's not interested? Or worst what if he's already taken? If I'm asking him out it's not just gonna be a one-night stand, maybe one day I'll get the courage to just ask. What's the worst that could happen? Going to another bookstore to find MoMA cards?