As a frequent business traveler, I don't have a problem with dining alone; I'm happy to take a book or tablet and read while eating. But I have experienced issues with service. Someone upthread (and a year ago) mentioned that single diners don't tip as well so they don't get good service. Maybe it's the other way around?

There's a casual dining restaurant very close to my regular hotel in France. It's not "fine dining" but it has a good variety of decent food at a fair price. And it's (by far) the closest to my hotel.

Over the course of maybe four years, I've eaten there three times as a solo diner and four/five times with a group (2 to 6 people). The difference in service is stunning.

My first time at this restaurant was as a solo diner and the service was poor. The second time was a year later with a colleague and it was so much better that I thought the first time had just been an off night. So I went back (within a week) on my own, and it was poor again. A year later with a group of six, and then a group of three, and then on my own. And there is definitely a pattern:

When I'm alone, they ignore me for a few minutes when I enter, before checking as to whether there's some slight chance I might be interested in eating. (Why else would I be here?) For a group, they are cheerfully prompt to seat us.

Alone, I wait an eternity before they take my order. For a group, they come before I've even finished helping my non-French-speaking friends with the menu.

Alone, I get the main meal and 15 minutes later have to ask about my soda or wine, which then takes another 10 minutes to arrive. For a group, they manage to bring all the meals and beverages at the same time.

Alone, they never come back to ask whether I want dessert or coffee when I've finished my meal. With a group, they were quick to ask what else we would like.

My French is just as mediocre when I'm alone as when I'm with friends (and in the group cases, most of my dining companions spoke no French) so it's not a case of language snobbery. On my own I usually eat a bit early so it's not overly busy. France is not a tipping culture so it shouldn't be fear of a small tip. I can only guess that the waitstaff find me awkward and avoid/ignore me. So I won't be going back as a solo diner. Their loss.