What do you think/say when people tell you that?
just order them a pizza with bitcoin. and when its delivered to their house tell them they cant have a slice, because ofcourse they think bitcoin is useless..
then order their girlfriend some roses paid with bitcoin and ask them. 'should i put this in my name, or do you admit bitcoin is useful and want the greetings card in your name and make your girlfriend happy thanks to bitcoin.'
if they are single and more into gaming. offer them a game on steam and then say "oops nearly forgot you dont want it because bitcoin is not really "a thing"
in short. explaining bitcoin to people is just too much for those not interested. but showing them how it works and how useful it actually is, peeks their interest