I Know I Know You

"Sorry!" I said the the person I just ran into. I hadn't been watching where I was going at all.
There was nothing for me to do for the next half hour before my next class. Every time this happened I had a tendency to wander around campus for the sake of having nothing else to do. Generally, I kept my head down; I'm not a very sociable person on cold days like these. But after having already ran into someone, I decided to face the world and try smiling at all who passed.
A familiar person rounded the corner about to cross my path. Casey Manwill. I hadn't seen her since I was 12 years old and we played soccer together. I waited for her to look in my direction before saying anything, but I couldn't bring myself to speak once seeing her reaction.
You know the times where you see someone, and you know you know them but don't know where? Casey had that look on her face for a brief moment. Seeing that caught my comment short and instead I smiled as she did to me. The courtesy smile. The "I'll feel like  a total idiot if I don't acknowledge you at this point."
I continued to walk on and tried not to chuckle. I took a quick glance back, just to make sure I'd really seen her, and saw her staring right back at me.
Hmm. Awkward.