Worst. Doctor. Ever

 is an unmarked Fallout 3 quest.

If you ask Sawbones in the Citadel to heal you he will wound you instead. With a high enough Science or the Robotics Expert perk you can fix Sawbones and receive free healing. Sawbones will not be particularly happy about it though.

This robot and Andy back in Vault 101 both prove that it seems the Mister Handy and Mister Gutsy model robots have some good fun saw tendencies when assigned the role of doctor.

Rewards

 * Free healing at the Citadel.
 * After repairing Sawbones' malfunction and receiving medical treatment, an effect called "Sawbones Precision" will appear in your Pip-Boy, giving you +2 END and +2 PER. The duration of this effect, and whether it can be gained again, is yet to be confirmed.