This happened when I lived next door to a pub. I was walking home with shopping in my hands, listening to Radiohead on my mp3. Some smokers outside the pub shouted at me. One said "Cheer up, love, it may never happen" and when I ignored him "SLAG!" I turned around but there was a small boy with them so I decided to tackle it a different way than my usual shouty-sweary-there-are-minimum-standards-of-public-decency-rant.
I found the pub's name in the telephone directory and rang the bar. I said that I had a right to walk the streets without such abuse and the barman agreed, apologised for them and said he would "have a word".