This might seem an odd question. I've been cooking for 40 years, quite successfully. Recently I've noticed on two different cooking programmes, Donal Skehan's Grandma's Boy and Jacques Pepin's home cooking on PBS, that both instruct to break eggs on a flat surface, but for different reasons. Skehan says that this is to prevent sherds of shell from getting into the mix, whereas Pepin says that this is to prevent the introduction of bacteria from the exterior of the shell. Well, I've always broken eggs against an edge (bowl, counter, whatever), but I tried this flat surface method. Shell shards frequently. As to bacteria, I would think that would be an issue only if one were collecting eggs directly from the coop. Thoughts?
NB: I can't say that I learned much from Grandma's Boy, but I love the goofy charm of it. I recommend it for a lark.