A world shortage of coffee is my bet

Not a fan of the word "apocalypse", too religious for my tastes, but whatever.

I'm always hoping for an asteroid, myself.
If it's not an asteroid, I'm going to go with disease.
A world-wide pandemic which wipes out nearly everyone.
Humanity will either start over, or vanish.

My vote is for "vanish".

I prefer to focus on the positive and push for progressive change. As an optimist, I have been doing this my entire adult life.

This includes gleefully giving the finger to anti-abortion protesters at Planned Parenthood as I drive by.

Since age 18, I have volunteered to help people in need.

If you are obsessed with doom and gloom, see a counselor.

7 - Stupidity.

YES

Each of these items begets the others.

Prep for what eventualities you can, stay fit, and just know humanity keeps the Earth in constant. One day the turmoil will be at YOUR foorstep.

If you mean wiping out all of humanity?
Nothing. We are amazing critters. In the geological blink of an eye, we have expanded and diversified into every possible ecosystem. We are immensely adaptable evolutionary badarses.
We make cockroaches look like wimps.
There are tribes in the Star Mountains of Papua New Guinea that are physically, ecologically and climactically isolated from the rest of the world, and would neither know not care if the rest of us disappear up our own arseholes, so a massive global ecological crash wouldn't get all of us.
Looking at the last mass extinction, the species that survived were medium to small sized adaptable omnivorous generalists, a category which we slot into very nicely. So even if it's us vs. an asteroid the size of Mount Everest, my money is on us.
The only caveat to this is if some madman creates and releases a biotoxin that will wipe out everything with a spine.
As for wiping out our current civilisation and causing a global population crash?
All of the above.
Climate change causing mass starvation and migration. This leads to civil breakdown, and a rise in fundamentalism along national and religious lines. It also allows epidemics to flourish with the breakdown of medical and sanitary infrastructure. The end game is nuclear war unleashed by the desperate dictators in charge of the three nuclear superpowers.
But that's just one opinion

I don't know about the 'apocalypse' term but for the end of us, I vote all of the above brought on largely by population overrun coupled with human shortsighted selfishness and stupidity.

An invasion of aliens from a hidden moon of Jupiter disguised as llamas with lipstick.

Zombies. duh.

I don’t think humans or life will be in peril until the sun turns into a red giant.

Self driving cars. Oh and the singularity.

Christian impatience

I don't think there will be one directly, but I do think that climate change will change our lives, and the lives of our progeny, forever. It's already affecting millions of people - the flooding in the midwest, fires in California, erosion and water damage on the coastal regions...

Honestly, I think it'll be disease and massive drops in male fertility. Its already happening.

Too many people.

Maybe disease, maybe brought on by pollution and climate change.

Climate change will bring on the rest.

Climate change. Also the USA's Fake President.

The number one thing that will cause the apocalypse is continued belief in it. This idea came from a biblical book.

Religious nutcases that believe in the idea of an apocalypse will be the cause of it.

It may happen, it may not happen, if it does it will most likely be all of the above working together, plus some others like resource exhaustion, grid breakdown etc. Few things in history occur for single simple reasons, historians have found forty plus reasons why the Roman Empire ended, most of which could never have been foreseen and all of which contributed.

But if you want to know the future then you can try a fortune teller, or a futurologist, neither work but they are your best shot. When at college forty years ago we went to a lecture given by a government advisor, very senior, who job was to predict future trends for the government, we were told that it was very special that he agreed to talk to us. Over the years I remember how many of the things he said came true; exactly none. History is chaotic and all attempts are doomed to fail.

Looking to the past as an example (don't ask for specifics I'm crap at backing up my opinions with facts) I'd guess whichever of the above happened on a big enough scale, the others would follow.

Apocalypse is a word from a fairy tale, but if you mean the end of mankind, I don't even think about it, whatever it is, it will come and I'm ready to go back to the soil and matter.

WHICH apocalypse? The Rapture? The breakdown of Society as per Survivalists? The re-election of Cheeto? Women forced to wear burkas while of course barefoot & pregnant? The rising sea levels?
You need to be more specific!