Never say u dont know, you always know wat other people are talking about to get involved within them, so make up the things, but if u really don have any cncept wat they are saying just agree wid sum1 wateva he/she says. They think u know every thing which makes ur attitude cool, but actually u dont. And when the person wid whom u agree is wrong just simply say "Awww! i thot it was rite i guess we are rong" Telling this makes u more wiser, as if u actually knew it!!