headcanon that when rabbit has depressive slumps the spine always tries to cheer her up but hes not very good at the whole cheering people up thing but for rabbit just not being alone helps a lot
(part 2) she usually just ends up venting to him because hes a very good listener and she just talks about whatever is bothering her or whatevers on her mind if shes sad for no reason and he'll just listen and put one arm around her shoulder and shes told him most of her Deep Dark Secrets during these feel jams because she knows he'd never tell anyone and its one of the few times the spines habit of keeping secrets comes in handy
being so sad when she's usually so chipper is kind of scary for her and she just hates it