His name was Steven, not cap, capsicle, spangles or whatever stark or the rest of the team called him jokingly or as a nickname.
he wasn't just a solider he was a person he had feelings too...so when he punched stark during fight practice a little harder then he should he simply smiled and looked down at stark
yea he thought, he was allowed to get upset sometimes, because even though the serum made him stronger faster, powerful. he was still just a guy from Brooklyn
and he was human and humans are allowed to make mistakes
he pulled himself from his thoughts and offered his hand to tony. "so best two out of three?" he said smiling as tony rubbed his now sore ribs
"whatever you say spangles"
Steve merely grinned