I was helping a close friend grow and build out his startup idea. i've known him for a while and we're still pretty tight. However along the way i realized that i wasn't into it as much as he was . the problem we were solving didn't bother me at a cellular level. Even though ive known him for a while it took me quite a bit of time to be upfront about it (i didn't wanto hurt his feelings) but as soon as we had a talk about it it was cool.