i think it's hard to tell the difference one on one...especially if they're really comfortable with you. it's like role reversal kinda...i feel more introverted and they feel more extroverted.
I definitely relate to this. when people first meet me they either think
1) he's mature for his age, confident and poised
2) fiery, charismatic and polarizing
3) an arrogant, self absorbed ass
4) angry/aggressive (this one always confuses me. people think I'm angry when I'm happy lol)
5) a goofy lunatic (more during middle/high school)
after they get to know me though, my 9 and 2 sides come out more and they say things like
1) I never knew you were such a nice guy
2) you're so calm and mellow, I thought you'd be the party type
3) I never knew you had such a feminine side
4) why don't you act like this more often (answer, because people disrespect my ass when I do)
5) you would make a better mother than me, and I am a mother
my INTJ friend on the other hand, people either think
1) he's a psychopath in disguise
2) he's secretly an under cover boss
3) he's just quite because he thinks he's better than everyone else
4) he's hawt (if they're female. I catch a ton of women staring at him when we hang out, but he never notices them lol)
5) shy
when they get to know him, they find out he's actually
1) the most intense person you'll ever met
2) full of energy
3) extremely wild and loves to dance
4) extremely combative
5) loves to talk (if he deems you intelligent and knowledgable about anything of consequence that is)