I think I found my favourite restaurant
I was thinking that it looks like the same diner. What if while Sam Wilson accompanies Steve on his mission to take down HYDRA he ends up hanging at diners when he needs a breather. One night, James Barnes sits down next to him and asks him about Steve.
Bucky can’t handle talking to Steve. Sam has experience talking to people going through PTSD and so he ends up being de facto therapist for Bucky. It gets to be such a regular occurrence that one night Sam walks into a diner to see Bucky waiting for him.