The main reason why people are quiet?

Okay well usually I am very talkative with my friends when I'm hanging out with them. But when I'm with my family I am really quiet. one day during dinner at the table i just started spacing out. and so my parents just think I'm this quiet shy person right? and my mom tells me " the reason you don't talk much is because you're too lazy to use your mind." that suddenly surprised me! i actually never looked at it that way. quiet introverted people are usually never thinking because theyre too lazy to think right? they just space out! so i'm guessing that's why extroverted are so outgoing because they have their mind working all the time. they have type a personalities while the introverts have the lazy type b personality.