Bittercup Runneth Over

 is an unmarked Fallout 3 quest.

When you first talk to Bittercup in Big Town, be polite and sympathetic. When she tries to hit on you, tell her you are not in any sort of relationship. You can now return to her once every 24 hours for a random present such as Squirrel-on-a-Stick or Nuka-Cola).