Sure there are days/weeks where nothing goes well, where you hear "I don't want you, I want mommy", but there are moments when you get the reverse, and even little things make you smile.
For example I was walking our child to daycare last week and had the following conversation:
"Daddy, what plant that is?"
"It's a rose"
"It has spikes"
"The spikes are called thorns, every rose has its thorn.."
Never had children? I'd have been happy, but I'm glad I did. Not everybody needs to, and the world would definitely be better place if relatives didn't ask every couple "When are you having children?", the moment they began living together, or got engaged.
I guess having children changes so much, especially for the first few years, that there's no easy way to predict how anything will turn out. I've changed in the past few years, for sure. Though part of that is just natural growth, and a consequence of changing country, etc, too.