Well, first let me say that being a parent is the best thing in my life (and there is a lot of very good stuff in my life), so don't over-index on what I'm about to say next. You'll be fine and better for it!

You might have heard the quote "To love at all is to be vulnerable. Love anything and your heart will be wrung and possibly broken."

YMMV but the lowest of the low are the times when you feel the reality that you have become utterly, completely, impossibly vulnerable in a way that you've never felt before. Speaking for myself, I haven't loved anything in my life even remotely closely to how I love my kids. Closest thing is my wife (and I really love her).

You go from... not wanting your plane to crash because, you know, it would suck to die and your spouse would be wrecked... to... my kids will grow up without me there to teach them, keep them safe, show them love. The angst I feel towards that is about 10000x worse than in how I thought about dying before kids.

Heck even your understanding of "my parents would be sad if I died as a 30-year-old man" changes. No parent should ever have to outlive their child.

Every headline that right now seems like a "sad story" - a parent losing a child, a child losing a parent, kids in cages, a daughter and father who are estranged, etc -- becomes an absolutely wrenching sadness if you even FLIRT with the idea of "what if that happened to me/my child"? You develop sensitivities that you are surprised at. You realize you have inherited an impossible and awesome responsibility of providing for, protecting, loving little blank slates of humanity... in a chaotic and dangerous world.

There's no answer to it except to do your best, and hope/pray that you never have to face the unfaceable.

That feeling isn't always present. But that's the dark shadow that occasionally crosses the sun.

Oh and BTW - this love doesn't just magically appear for everyone right away. I know lots of fathers especially who don't feel much right away, but as you see your children go from blobs to little people, you fall in love with them. So don't sweat asking yourself if you're feeling it. Just let it happen. :)

- Any health problems for anyone concerned in the first couple months (which is when it's most likely, for the mother and baby in particular, obviously) will be really, really bad, as far as making those weeks much worse than they'd otherwise be.

- If you get very unlucky (sometimes) or suck at sleep training (way, way more often) get ready for years of bad sleep, yourself. If you're good at this the dreaded "sleep zombie" stage of parenting is only ~2-3 months long, though, so no big deal in the scheme of things, and even better if you've got a spouse who isn't the kind of person to "punish" their partner any time they have to be awake by making them also be awake (lots of people truly are like this, and I think it's nuts, if you do some good trading-off with one another, then the first couple months are actually really easy and you'll only be sleep-deprived like half the time, at worst)

- If your kid is sick, at all, then sleep in those early weeks will be exceptionally terrible, as kid illnesses tend to manifest in frequent waking & crying that can't always be assuaged with milk or rocking or whatever. Even a mild illness can make those early nights damn dark, and you may have trouble figuring out what's wrong (may take shopping for a doctor to find one who won't just rudely brush you off as a newbie parent with a "colicky" baby and actually listen to you and try to figure it out)

- They can be incredibly expensive, for all kinds of reasons, including but not limited to healthcare expenses (in the US), damage (ours have done over a thousand dollars of damage to stuff around our house in some years, more if we counted the rate of wear on e.g. flooring or the cost to pay for repairs on all kinds of things that we were able to do ourselves very cheaply), education (paid directly or, more commonly, in much higher housing expenses than you'd otherwise have). Oh and as they get older, food. (clothes and toys are negligible expenses compared to the rest, unless you don't want them to be)

Basically if no-one gets sick and you take sleep training seriously, they're just expensive and everything else is barely a problem... until they get old enough to start going places on their own, and then you get a whole new set of worries :-)

Every low you have now, but dealing with it while responsible for the life of a tiny person you inexplicably love more than anything else in the world, on zero sleep.

The individual freedoms that you've taken for granted your entire adult life will disappear overnight, and you'll experience a months-long grieving process while also exhausted from lack of sleep.

You'll get over it after a few months, though, and then there is your beautiful baby smiling at you.

Immediately it’s the sleep deprivation which is basically a form of torture, remember. Then there are anxieties about their well being and their health on occasion. Later in teenage years about how they are starting to run their own lives and are they maybe veering into dangerous areas (eg hard drugs). Then there are worries about how their life is turning out as adults. The anxiety doesn’t stop but it’s also the most important adventure in your life that no amount of traveling, home improvements, social media bragging can match despite what the child-free crowd seems to believe.