Please don't list this on a work's page as a trope. Examples can go on the work's YMMV tab.
Tear Jerker: 2 Broke Girls
Max's very visible pain when she finds out Johnny has a girlfriend.
Max's good bye to Chestnut when they have to send him to a shelter for the winter.
Max telling Caroline that she uses store-bought cake mix because no one ever taught her how to bake, or how to do anything, and asks Caroline if she really thinks that Max should get her mother a better birthday card.
When Max is electrocuted and Caroline thinks she might die, she begs Max not to die, trying not to cry, because she's her best friend.