sister knows it all

at kaiser getting allergy shots talking to my dad about my $240 school books.

me: we can get ebooks for my textbooks
dad: well, is it cheaper?
me: yes, about $40 cheaper than a new hardcopy of the book
sis: you are stupid
me: huh?
sis: ebooks are stupid. they are glitchy. they suck. screw you for wanting them
me: well, it might be worth a try
sis: I have friends who go to your school and they say they suck.
me: and you're the expert suddenly?
sis: yes dumb poop
sis: you're an idiot

Edit: Good little Christian sister can't say ass, so she says poop instead. It was everything I could not to slap her.