I get this as well. While it's been a long time since I've dined out somewhere nice alone (somehow the awkwardness doesn't quite apply when you're somewhere mid-range at lunch time, or at stopping off at a bar for a burger and a beer and some along time), it's always felt a touch awkward.

I guess it's because food is powerfully social. Whether its the idea of breading bread with a stranger when you're travelling, or eating dinner with your family, or taking your other half to a nice restaurant, there's very strong social imperative when it comes to eating - and it's one which exists in pretty much every culture that I can think of.