what will trigger a market correction

We read and hear all sorts of thoughts and ideas about an impending correction, even down to some predicting the day etc.

There will have to be a catalyst for it to happen, what signs are there (apart from markets being at the highest, but adding time and inflation they are not nearly as high as what people think etc)

So share thoughts what will trigger, is it USA realising they are in deep p** or china softening its own market thatwill de stabilize ours.
Your thoughts and any facts if you have please, we can all learn.

Maybe the market will go to 7000/14000 respectivly before a downturn, are the p/e'sat hiostoric highs? i dont think so, and which stocks will be the best to have if it occurs?

And if people are thinking it will occur why dont eveyone sell and then that would make it occur, like a self fullfilling prophecy.

I havent even had a glass of red tonight and I am rambling