The reason you feel that way is because social anxiety correlates with anhedonia. The person doesn't engage in playfulness which is the basis of social connection across mammals. Because they aren't playful, you perceive this as "deepness."
This cognitive fallacy connecting deepness / seriousness to substance, and connecting playfulness to triviality and frivolity has unfortunately affected me (I remember arguing it in high school English class!)
Consciously adopting a "playful" attitude fixes my social anxiety, and adds charisma and humor to my character.
I have never seen a place more playful than a roulette or a craps table in Vegas, people high five each other, they form groups they trash the casino when the bank wins... but it is very shallow and not very deep, it lasts a couple of hours and then each of the participant go separate ways.
This cognitive fallacy connecting deepness / seriousness to substance, and connecting playfulness to triviality and frivolity has unfortunately affected me (I remember arguing it in high school English class!)
Consciously adopting a "playful" attitude fixes my social anxiety, and adds charisma and humor to my character.