You think you can always write that book, or climb that mountain, or whatever, and then you realize the window has closed. The usual way to avoid being taken by surprise by something is to be consciously aware of it.
Back when life was more precarious, people used to be aware of death to a degree that would now seem a bit morbid.
Since there didn't seem any way to answer this question, I stopped wondering about it. That gave me a way to answer the question, and the answer is that life actually is short.
Having kids showed me how to convert a continuous quantity, time, into discrete quantities. If Christmas-as-magic lasts from say ages 3 to 10, you only get to watch your child experience it 8 times. It means arguments of the form "Life is too short for x" have great force.
The things that matter aren't necessarily the ones people would call "important." Having coffee with a friend matters.
You won't feel later like that was a waste of time.In middle school and high school, what the other kids think of you seems the most important thing in the world.But when you ask adults what they got wrong at that age, nearly all say they cared too much what other kids thought of them.It's almost the definition of bullshit that it's the stuff that life is too short for. If you ask yourself what you spend your time on that's bullshit, you probably already know the answer.And yet bullshit does have a distinctive character. Unnecessary meetings, pointless disputes, bureaucracy, posturing, dealing with other people's mistakes, traffic jams, addictive but unrewarding pastimes.Otherwise these people are literally taking your life. Which means we will increasingly have to make a conscious effort to avoid addictions — to stand outside ourselves and ask "is this how I want to be spending my time?"As well as avoiding bullshit, one should actively seek out things that matter.You need to make money, and making money consists mostly of errands.Indeed, the law of supply and demand insures that: the more rewarding some kind of work is, the cheaper people will do it." And odds are that is in fact the bullshit-minimizing option.If life is short, we should expect its shortness to take us by surprise. You take things for granted, and then they're gone. After my mother died, I wished I'd spent more time with her. And in her typical quiet way she encouraged that illusion. I think a lot of people make the same mistake I did.