The context with my therapist was her telling me i was reliable, and my not quite willing to take that unqualified. Reliable enough, i said. She was trying to encourage me to accept that, and i could get her point as she talked about "good enough mothers" in the abstract. My sister worries about her failures in mothering, but she is certainly a good enough mother. I can understand how "good enough" doesn't point to someone just doing the minimum for selfish reasons or going through the actions, but points to complications and externalities and failures that makes an absolute judgement perhaps out of reach. I got her point.
And when my therapist tossed off the aside of "Your mother was good enough," i know she was doing it because -- even if i have a hard time feeling it some times -- i am professionally successful, working with people i like and doing things i enjoy. I have meaningful things i care about. I have an excellent relationship with my spouse, my sister, my father -- and -- at this point in time, with the person she is at the moment -- my mother.
For me the important thing with my therapist was that she quickly noticed the mistake and made every effort to take care of me after that.