Perform a social experiment:
don't buy your round for a month and chart your relationships.
( Kamikaze Stoat £4.09, Fri 10 Sep 2004, 15:25, archived)

I've tried it.
No one complains when you're there, but they do stop inviting you out, so you just have to do a bit of extra research to find what pubs people are in.
( Newington, Fri 10 Sep 2004, 15:32, archived)