Poor Berry Punch. Drink directly from the punch bowl at one little party, and everyone suspects that you may have a problem. Still, she's a fun background pony for having displayed more of a distinct action than most, and who can really blame a pony for cutting lose now and then in social situations?
Of course, not all fans go the lush route, which is always nice to see. I've seen speculation of her being related to Cheerilee as well, and they do have some similarities (even if we've seen such things don't often run in the family.)