When I was travelling I split off from my friends for a couple of weeks and had to eat alone. I quite enjoyed it actually.

Doing a bit of discreet people watching is always interesting (to me at least) and it was even better being in a foreign country where you can see the differences between your own culture and theirs.

I did feel a bit embarrassed at first but once you sit down and order what you like its fine. No one pays you any attention at all.