Writing is part of you, your very soul, defines you. Writing is special. It can help make you feel special especially when you’re happy with the work you produce.
The troubles of life overwhelming you and your work sometimes. Feeling you're not conveying in words the emotions you want to convey (we all know those times when words are not enough but in a writer's case, this is doubly frustrating as words are all we have).
Not feeling special because you're unhappy with the work you produce! (I cheer myself up here by reminding myself there is little a decent edit won't improve).