I used to, a lot. When I lived in London. Went to All Bar One in Nottinghill with papers and fags (the good old days!), all the time...and other pubs...like the Dove in Chiswick and a few others along the Mall there...decent pubs iykwim. Would drink heaps of wine/have a few pints. Enjoy myself. Honest! Not really in the evenings though.
Would I now? Yes if I could find a babysitter and if I lived somewhere more anonymous.
I did a pub crawl alone a few times (sounds like I don't have mates. I do but worked shifts back then and they weren't usually available for pub crawls on my days off!). Had a bloody good time!
I also holidayed alone - a week in Athens, two weeks by a lake in Italy. I even emigrated to Australia totally alone! I have met lots of wonderful people and even made some close friends going it alone. It's not so bad. So long as you have a bit of dutch courage inside you and a big smile and don't get into convo with anyone who seems slightly dodgy.
Am going to have to start doing things alone again big time soon...
Need to move somewhere anonymous again.
Do it! If it's crap so what? It can't be more crap than staying in and wishing you were out....start small...go to a pub that's not packed or a party-pub, have half a cider and keep pretending you are texting/waiting for a text. People will ignore you quickly and you can sit and enjoy-ish. Get the feeling for it.
It's easier if you live in a city though and you can go drinking around your "manor".
Why do you ask? (after all that rambling...no wonder I went out alone. No bugger could put up with me. ha ha )