Ideally you'd be able to accurately gauge your progress without having intense negative emotions attached to it. Certainly it shouldn't undercut a person's feeling of validity in the world.
I think "feeling behind" means different things for different people, depending on the experiences in their formative years they have associated with the thought of being behind. The ideal response to the feeling depends on what the feeling is.
Yep. I think that if we have a bad feeling about being behind, it's more likely because there's something else that we Actually feel bad about, but "being behind" is an easy thing to attribute it to. More likely there are some childhood/family/psychiatric issues being unaddressed. At least, I've discovered this about myself.
I think "feeling behind" means different things for different people, depending on the experiences in their formative years they have associated with the thought of being behind. The ideal response to the feeling depends on what the feeling is.