My sister is a taddle-tale machine, and she's 18 years old. As the younger sibling, I'm subjected to all the blame because I'm known to be irresponsible and morally corrupt.

"MOM, GINA DIDN'T DO THE DISHES OMG SHE'S SO HORRIBLE" Well, yeah I didn't do them yet because YOU'RE baking a damn cake in the kitchen and taking up the whole kitchen space. And the thing is, when I get blamed for something, my mom ALWAYS sides with my sister, and then she lectures me about responsibility and how I should be more like my sister.
And get this, once she's done lecturing me about that one subject, my sister interjects with something like "OH! AND GINA DIDN'T EVEN TAKE OUT THE TRASH YESTERDAY!!", which causes my mom to continue her lecture and add on to the blame. It's like a chain-reaction of blame, and I'm the scapegoat of it all.