Why day-drink during work if you don’t get drunk?

I have seen in movies (so this may not be valid in the real world, but assuming it is) that some character will consume alcohol all day during work hours (not too much alcohol but enough to keep them sane). My question is what is the point?

I am all for alcohol but does it somehow help to be drinking vodka while working in order to deal with people? I have been meaning to try this but do wish to know if its only applicable to movies or if it is real world thing