Social anxiety is not a thing that you either have or you don't. Everyone has social anxiety to varying degrees. To claim that people with social anxiety don't live as full or enjoyable lives as everyone else is just plain wrong. What is a "full and enjoyable life"? Is it having an average amount of social anxiety? But then you don't get to do all the cool shit that the people with very minimal social anxiety do. Is it having minimal social anxiety? But then you might end up doing things that you'll regret later i.e. having your silly picture/video go viral and then you might even end up developing social anxiety as a result of the entire world/country/city knowing your embarassing moment.