Actual personal disorders are extreme and can typically result in disruption of one's ability to maintain LTRs, hold down jobs, etc., and heavily inhibit/restrict behavior/interaction.
The DSM traits for APD are as follows:
1. Avoids occupational activities that involve significant interpersonal contact, because of fears of criticism, disapproval, or rejection
2. Is unwilling to get involved with people unless certain of being liked
3. Shows restraint within intimate relationships because of the fear of being shamed or ridiculed
4. Is preoccupied with being criticized or rejected in social situations
5. Is inhibited in new interpersonal situations because of feelings of inadequacy
6. Views self as socially inept, personally unappealing, or inferior to others
7. Is unusually reluctant to take personal risk or to engage in any new activities because they may prove embarrassing
Typically these things result in living a heavily restricted life, versus just having feelings but still being able to function and ignore them. There's a hypersensitivity to criticism and an excruciating sense of shame resulting in a severe need for personal image management -- which means you only let people see the positive aspects of yourself or you restrict your interactions accordingly all to avoid having criticism come in that exacerbates the sense of self-unworth. Situations where you can't operate at peak efficiency are viewed as very dangerous. You are heavily monitoring both your internal feelings as well as the immediate reactions to you from the other people around you. If someone is not very adept and/or hyperaware of cue-monitoring (to the point of assuming the worst of the smallest cue that people they interact with is offering), I'd think maybe it's a different issue besides APD.
As far as presentation, APD folks typically come off as restrained and nice on the surface, potentially reclusive, while inside they feel deeply wounded by typical interactions and have to fight off waves of perceived negativity that others are likely not even imagining. It's all because their own pervasive feels of imperfection and unworth lead them to expect everyone else to view them similarly... hence, avoidance.
I think around 30% of those actually diagnosed as having social anxiety disorder can be diagnosed with APD.
