No. In a bubble, everyone believes something is undervalued and is desperate to get in. 'I need to buy Pets.com at $100 because in a month it'll be $1000!' Or 'I need to buy Bitcoin at $350 because it's taking off to the moon!' This causes the general surge in prices where everyone buys in because now it's cheap ('the Communist Party has guaranteed stocks as an investment, so I can't lose by buying now'), eventually leading to the crash when suddenly people begin fervently believing everything is way too expensive (and so they should sell).