Even before they have kids, most people have pretty strong opinions about how parenting should be done. At some point or another we've all been guilty of claiming that we'd never let our kids watch too much TV, or feed them processed food, or look at our phones while our (hypothetical, still nonexistent) children played on the playground.
Those plans hold up really well, too...right up until you have an actual human child. That's when you discover that sometimes distracting kids with the TV is the only way you get to take a shower, and processed food is better than your kid starving because he refuses to eat anything but buttered bread for three weeks in a row.
Don't even get me started on the sainthood that would be immediately rewarded any parent who actually managed to look at her kid each of the 5,489 times he yelled, "MOM, LOOK AT ME!" on the playground.