Parents are gullible, and babies are manipulative.

Baby: [acts adorable]
Parent: Oh, you’re the best! Love love love!
Baby, ten seconds later: [screams inconsolably]
Parent: Shh shh shh shh
Baby, two hours later: [still yelling despite being fed and changed and burped and healthy]
Parent: omg what were we thinkinggggggg
Baby: [stops crying, acts precious]
Parent: You’re so adorable and perfect, you never do anything that’s frustrating.

Evil, evil babies. They’re good at getting us over the immense frustration of being cried at right in our faces.