Somewhere in our deep dark roleplaying history someone made a mistake. They had misread the racial description for Elves and rather than making them immune to normal diseases had made them immune to normal poisons. This had a consequence of making it impossible to get an elf drunk.
When my last campaign started I wanted to correct this error and pointed out the rules where it shows the immunity and resistance roll mods to show the players that we had been doing it wrong all this time. I was amazed at the players reactions (if those that wanted to play elves.) The ability to drink anyone under the table was really important to them despite the fact that is was a blatant mistake on our part.