The subtlety with the Ugh Field is that the flinch occurs before you start to consciously think about how to deal with the Unhappy Thing, meaning that you never deal with it, and you don't even have the option of dealing with it in the normal run of things. I find it frightening that my lizard brain could implicitly be making life decisions for me, without even asking my permission!

Relational frame theory is a theory of language cognition that attempts to explain this. The basic idea is that we form associations between thoughts, and when we think of an element in a relational network with another element that causes a painful emotional reaction (shaped as you describe), we have that flinch, even if the element we think we are reacting to is benign. And as you describe, this can lead to behavioral avoidance.

I'm currently in acceptance and commitment therapy which teaches you how to distance yourself from those thoughts and see them as language (and not the proverbial "tiger in the bush"). I'm not proselytizing (one of the more distasteful inclinations of a therapy patient), nor describing it in enough detail to be therapeutic, but I've found it much more helpful than straight cognitive or positive therapy.