There are so many historic extremes now, on at least a 170-year perspective, that "bad stuff" will happen.... another global financial crisis. In the coming crisis, I think it is highly likely that it will be more severe than during the 2008-2009, where Australia avoided the worst of that crisis, because China's massive infrastructure stimulus rescued Australia.
Some argue that it is "it is too hard" to try to time the market, and therefore you should not try. The last 170-years of share market experience, strongly indicates that it is negligent to ignore medium-term market risks and therefore, if your care about your financial security, this is an issue that it is critical to confront. Share markets do NOT always delivered good or even positive returns over the long-term, and there are warning factors that you should look for.
This is how Nouriel Roubini put it in AFR 20/Feb/2020:
In my 2010 book Crisis Economics, I defined financial crises not as the “black swan” events that Nassim Nicholas Taleb described in his eponymous bestseller, but as “white swans”.
According to Taleb, black swans are events that emerge unpredictably, like a tornado, from a fat-tailed statistical distribution. But I argued that financial crises, at least, are more like hurricanes: they are the predictable result of built-up economic and financial vulnerabilities and policy mistakes.
Nouriel Roubini was of the few people that forewarned of the 2008-2009 Global Financial Crisis.
Note: This is not financial advice. See advice before buying or selling securities. Acting on these comments is at your own risk. The above comments are only general in nature.