A Knight of the Seven Kingdoms sets itself apart from other Game of Thrones shows in the first few minutes with the inclusion of cutaway gags: abrupt cuts to scenes past that add a punchline to a line of dialogue. When eulogizing the recently passed Ser Arlan of Pennytree, Dunk mentions how he never beat him when he didn't deserve it, only for the scene to cut to a quick-fire montage of all the times when, presumedly, he did deserve it.
We don't know much about Dunk's beginnings, but to be fair, he didn't know much either. He grew up an orphan in Flea Bottom, the slum near King's Landing. He had no idea who his parents were, but figured he was an orphan and probably a bastard. (Some fans suggest he could be related to Brienne of Tarth, since he was tall just like her, but that's still unconfirmed.) He made a life by scavenging all kinds of meat for establishments that made "bowls of brown," the go-to food of Flea Bottom.