That's a very good question, why do you think?" or, "Let's go look up the answer."
Almost every book is written and published not with the goal to help you or your child, but to make money. Keep this in mind. As a result, most of what you read in books really is crap.
Follow what Donald Winnacott said about parenting -- the best kind of parent is not the "perfect" one, but the "good-enough" one. The good-enough parent remains sensitive and aware of a child's basic needs (warmth, food, emotional security) and responds to them directly. Everything else really isn't that important and being stressed about it with your kid does more damage than good.
21. Many aspects of parenting will not bring you joy or happiness
Your children do not belong to you. They are not your possessions and their accomplishments, achievements, failures and everything in between belongs to them. Your children were born as complete human beings, and there is nothing more damaging and hurtful than to deny someone's humanity. For some bizarre reason children are forced to endure this as a matter of course by a lot of people who ought to know better.
Children don't ask to be born, and they do not owe you for parenting them-- you owe them because you brought them here. "I was a good parent" is not a thing you get to brag about, it's the bare minimum that the vulnerable little people in your care deserve.
Your job as a parent is not to make your children happy. Your job is to give them the skills and tools they will need to function and make themselves happy going forth in the world. That means there will be many times you will have to do things that makes them unhappy and in turn that makes you unhappy. A lot of aspects of parenting will not bring you joy or happiness. Remember it's better for your child to experience hard lessons with the soft comfort of a supportive and safe home to lean on, rather than putting it off so the first time they experience hard things is when you're dead and not able to help support them through it.
Don't lose your identity. As a parent you are the first example of an adult that your child will look too- it's healthy and good that they see you are not just their parent but a person with passions and a life beyond being mom or dad. Dating your spouse and cultivating a life together as lovers rather than just parents is not detracting from your children.
You will mess up. You will mess up repeatedly because there is no manual for how to do this. It's ok that you mess up, in fact. But your child is watching, so when you mess up, apologize sincerely to them without precondition or excuses, and actively work to not repeat the mistake. Your child will forgive you if you are sincere and loving.
The more people who love and care for your child, the better off they are. Don't hoard your child's love or be possessive of it. Multiply love in their life.
It's easy to write off the feelings of children, especially small children.. but when you diminish and mock the "little" things when those children grow older and have "big" things, they don't trust you or come to you. If it matters and feels big to your child, you need to treat it appropriately. If you don't consistently demonstrate that even the little things are treated with dignity, don't be shocked that the trust you eroded and destroyed means they don't come to you with anything.
Oh and when they're a newborn and you can't figure out why they are screaming their little head off in the baby swing - put that swing on full blast. I've yet to meet a newborn who doesn't love the swing, they just like it going full blast. Strap em in and let it rip.
You're gonna be washing a lot of bottles.