Lunch With My Sister

Chips & Guacamole, Pesto Chicken Quesadillas, Pepsi, and a Banana Smoothie bought at Mesa Verde

$29.85 plus $10 tip*

We kinda went dutch on this one. She paid $23 making my share $16.85. I don't really feel bad for paying less because I usually buy her breakfast when she comes to town.
Does this make me a bad sister?

*Is this a good tip? She was a good waitress and she even called my work to tell them my sister left her glasses behind. (She recognized me when we came in as the "video store girl")