@emp, if the winners in a restaurant are coffee and tea, why wouldn't you open a place that only sells those?
@RedFire, I imagine that one of the things that matter for a coffee shop is that country's coffee culture.
Back home, we have a pretty strong coffee culture, a lot of the social interaction happens over a coffee (meetings, dates, catching up, etc) but then again, I've seen a lot almost empty during the day. The ones who were successful were the ones who created a lunch menu and added some unconventional desserts, they're opening their 3rd location now.
I had a friend who opened a pub near a college camp in Bucharest, during the day it was completely empty, he only had customers, full capacity, in the evenings when he organized parties but at the end of each month he injected money in it to keep it alive. After less than a year he close it down.
I'm in London right now and I have this amazing coffee shop near my uni, small one, owned by an italian family, they have 4-5 tables inside and they have a lot of take-away's but I think it's only enough to keep them going and bring in a small profit.
Then again, you have coffee shops like Nero, that italian coffee shop in the UK, that now has over 500 locations. Take a look at their expansion
Caffè Nero