Street sweets, or things best eaten on two feet

At some point in my impressionable youth, I was told that one should never eat while standing up. This well-meaning killjoy of a tip was probably given to me during one of my mother’s various dieting phases, the idea being that one can’t be fully mindful of what crosses one’s lips unless one is seated, preferably with a knife, fork, and a napkin. There’s a good degree of truth to this, certainly,