1) Generally, the nature of a bubble is that nobody knows when it will pop. People knew about the U.S. asset bubble in the mid-2000s for years, but even those not caught up in the bubble mass psychology couldn't accurately predict when it would collapse. The same was true of the dot-com bubble around 2000. You can be right that there is a bubble, but be far wrong about when it ends.
2) There was a stock broker looking for new business. He cold called 512 people (he must have been a quant); half he told to sell X stock, half he told to buy. The next week he called the 256 for whom he'd made the right prediction and did the same again: Half he told to sell, half to buy ... several weeks later he was down to 16 people. He called all of them and said, 'look, I was right 5 times in a row ...'.