A false friendship that two people honor because they feel like they have to, not because they actually want to.
This generally involves a male and a female relationship in which person A likes person B and hopes to be more than friends, while the person B keeps person A there out of sheer pity, which results in person B thinking he or she has a chance with person A.

When you eat dirt for the first time and leave your family to build a shack in the woods