Vietnam, like Thailand, has an odd attitude* to vegetarian food. To the extent that people are religious, they’re mostly Buddhist (or around here also followers of Cao Dai, which seems even more pro-veggie). In our little town, there are three completely vegetarian restaurants near the hotel where we stayed, and the country’s being covered by a chain of vegan restaurants called “Loving Hut”, run by some endearingly/disturbingly wacked-out people (http://en.wikipedia.org/wiki/Ching_Hai).
On the other hand, any non-specifically-vegetarian restaurant will usually make no concessions to vegetarians whatsoever: even vegetable dishes come with little bits of meat floating in them (“to make it delicious” — cheers). Very few people here are actually vegetarian: most of the vegetarian eating that goes on is on the first and fifteenth days of the lunar or calendar month, fish-on-Fridays style. My theory is that the few who are completely vegetarian would avoid non-vegetarian restaurants because they want their food prepared in a purely vegetarian kitchen (understandable here).
As compensation, however, the supermarkets do offer a smorgasbord of tofus (tofi?), and tins to raise a smile:
*Odd attitudes are naturally foreigners’ rather than mine.