I wonder, OP, how many children you have?
When DS was born I was supremely arrogant, my baby slept when he should, ate when he should, he did everything by the book - he hit all his milestones in the average time, and was a happy easy baby. He rarely cried and so far as I was concearned having babies was easy and I could prove it.
The gods smiled upon me and DD followed. I was sure I was cursed. DD didn't sleep, screamed for hours on end, vomitted, scramed, sh@t through the eye of a needle, screamed, didn't feed, screamed, didn't burp, screamed. I was a failure as a parent. Our check list was a,ways started with checking her nappy, she HATED a dirty nappy. Forget feeding or burping - that NEVER worked. In fact she was often only settled when bathed.
My pet peeve is supremely arrogant people like I once was, and people who assume all babies are like robots or scarves ( one size fits all )