I was at a lunch with some other writers and the subject of agents came up. As it does. One of the writers present was finding that their agent was difficult to talk to - they kept discussing books the writer might write, rather than the one they were actually writing. The writer felt confused - did their agent like what they had actually written? Should they change direction and do something different? Or was the agent just passing the time by talking about what was hot at the moment?
Whatever stage you're at, published or unpublished, it's easy to get de-railed by throwaway comments. The writer has to stay sensitive, but also develop a thick skin. You have to really believe in your work, because otherwise you're vulnerable to being undermined, even by those who should be supporting you.
I've known writers be utterly demoralised by casual remarks made by parents, partners, friends. They make them because they don't understand the writing process. Agents (and editors) don't - or shouldn't - have that excuse.
For anyone feeling a bit bruised or battered by 'helpful feedback', whoever it may be from, I suggest having a look at this wonderful Mitchell and Webb sketch. It sort of sums it up...