Did you ever watch the movie The Man Who Came To Dinner? In it, there's an obnoxious, demanding houseguest named Sheridan Whiteside who seemingly will never leave.
In my family, when we were kids, we were always having various cousins living with us. One cousin, Mervyn, stayed the longest. He was obviously unable to fend much for himself. One day, he ordered, imperiously, "Cut that pie!" I reacted by saying, "Cut the damned pie yourself if you want some!" When he started to cut the pie, it was obvious that he had no idea how to cut a pie as he was HACKING at it. I immediately took over the knife. ["CUT THAT PIE!", uttered with the unique Mervyn inflection, has been a family saying ever since.] See the video HOW TO CUT A PIE IN 10 SLICES:
Over the years I have been stunned by the number of people I've encountered who do not know how to cut pies and cakes. At functions, I am immediately asked to perform the task.
While working at International Harvester, a guy came from another department to ask me to come to his department to cut a cake for a celebration. As I did not know the guy, I asked him why he was asking for me and he said, "Dino the Inspector said you were the only one who knows how to cut a cake right!" It was probably because I was the only woman there. Dino was the one who usually ordered cakes for our department's occasions. Once Dino asked me how I'd learned to cut the cakes. Dumfounded, and not thinking that cake cutting demonstrated any particular talent, I answered, "From my mother, I guess." He said, rather plaintively, "My mother never did things nice like that." Dino later asked me to teach his girlfriend how to cut cakes and pies.
Martha Stewart and other companies sell pie cutters (see above) at ridiculously high prices. Although I am a gadget lover, I say, "What's wrong with a knife?"