"Sam having to deal with being around Bucky later and not knowing how much he remembers... Sam thinking he can/must deal with it all by himself because after all his job is helping people" oh ANON, that's my language you're speaking, a good man impaling himself nobly & needlessly on his own goodness, turning virtue to vice... delightful

and naturally this springs to mind first for Bucky, but even a Rumlow/Rollins/OC-who-worked-with-Steve would add that extra "not wanting to tell Steve because he'll blame himself for this personal touch on HYDRA's part" edge