It's been just over a year since the last stock market crash, and investors are wondering if another one is on the way. With economic momentum slowing as the effects of fiscal stimulus wear off, it's no surprise that equities seem to be fading, too. Meanwhile, labor shortages and stretched supply chains remain lingering issues, while inflation is starting to be passed on to consumers. It seems like this should be a risk-off environment. But retail traders appear to be the only investors having a good time. Does that mean we're in a bubble and due for a pop?