Asklemmy

How much more annoying the (much) younger generations would be.

If the ultra rich find you out, you can expect lab-rat life, at least until all modern systems collapse. Death is the only thing those suckers fear, because regardless of their net worth, it comes for all, even if late. They would do anything to find out your trick

Idk id be super depressed if I was able to experience my family, friends, family's children, and so on die.

You'll be perpetually behind the times. People tend to get set in their ways even by their 30s. You'll constantly lag behind the trends, language, and tastes of the younger generation...

If you were the first to be immortal, you may not have the best version of immortality and it may render you incompatible with better, future types of immortality. Like magical regeneration that prevents you from getting a personality upload to a cyberbrain that is a million times faster and smarter than the squishy biological brain.

One of my books features an immortal protagonist and I've as such thought about this quite a bit. More than the answers already provided here, what I found interesting as a writer was the balance I needed to find between making an immortal detached from mortal values while still being engaging to mortal readers.

Said as a pithy question, if you can outlive everyone's decisions and mistakes, what would it take to make you do anything at all?

I'll say no one can truly know. Unless you are yourself immortal

Just depression in general. I don't want to live one lifetime, let alone never being able to die.

If you're immortal in a body that isn't broken then that might be a different story, but you'd still grow to love people only to have to lose them and go through that pain over and over.

outlasting humanity and all its trappings

Man, you took it too real too quick

If everyone gets to be immortal, imagine never being able to get rid of dictators. Putin's 600th won election.

People in the future wouldn't be allowed to have children, Earth will be filled to the brim with very old people and very few new ideas.

No matter how old, how experienced, or how talented you are, there's always some Asian kid that's better than you.

You gain some kind of magical immortality ahead of everyone else... But then, a few hundred years later, everybody else gains some kind of technological immortality that's way cooler/better, that your magical immortality is incompatible with. And you get left behind as the slow, weak, dumb, magical, biologically immortal human while everyone else is zipping around at light speed with gigabrains and shiny chrome spaceship bodies with 20 additional senses.

If it's just you being immortal, loss of all family, and friends, and loss of new friends, rinse repeat forever. Eventualdieyoull watch society collapse and regrow (possibly), and the planet will die. Immortality is forever after all. Then you're left alone on a deserted dead planet. Electronics you have will eventually break and fade away to time. The sun will grow and die off, and it'll burn because you're immortal but still stuck on a planet that'll get enveloped, eventually. Living forever would be terrible unless it was forever until you died of something physical, just not age and illness.

Read this on the largest number every used in a mathematical proof.

Then ask yourself, if you think you could handle this number in microseconds let alone an eternity

https://waitbutwhy.com/2014/11/1000000-grahams-number.html