I have learnt from repeated, harsh, crushing, bruising experience, to trust my instincts. Even when they seem counter-intuitive. I will regret it otherwise.
The analogous lesson has so far not been applied to how I assess the needs of friends.
For all of the praises my friends have about my character, I have an above average habit for letting them down.
But more to the point, I have the habit of letting down ones I didn't expect to, which are always the worst possible ones to have let down in any situation.
I'm trying; the first step is admitting there's a problem, but it's still something I seem to get very wrong a lot of the time.