I wouldn't think less if you for not having a Facebook, but i'd probably become less of a good friend to you simply because of logistics.

I (as anyone who had traveled, I'm sure) have a lot of friends on Facebook whom I met on a trip. Maybe we only had a beer and hung out for 3 hours. But since we added each other on Facebook, we're able to keep in touch. I talk to foreign friends via Facebook all the time.

So instead of my buddy in Brazil that I met in NYC, you'd just be some random cool guy I knew once.