There are already much more detailed answers than this one is going to be but: all bubbles pop. The very nature of the bubble is people are walking around with

There are already much more detailed answers than this one is going to be but: all bubbles pop. The very nature of the bubble is people are walking around with assets that are misvalued. The greatest trick in finance though, isn't spotting overvaluation: it's figuring out when reality is going to kick in. Every time a price defies gravity (housing, tech stocks, the UK economy), there's plenty of people who see the crash coming. But timing is everything.