^ It's very similar for us software people. When someone reports a bug to you, you know they're helping you make your software better, but (and their delivery can unintentionally excercabate this) you still have to fight the base human reaction to having your existing work "attacked". All the more so if it was non-trivial to even get that far and you've become invested in a solution. Learning how to deal with and integrate feedback can be a challenge.
Empathy on both sides helps a lot.