When the average retail investor (regular investor) gets excited about being in the market, it's a sign that we should be very cautious. Retail investors especially get it wrong at the extremes (market tops and bottoms). https://www.zerohedge.com/news/2018-02-12/retail-goes-all-e-trade-adds-37100-new-accounts-154
Trading seems fun, exciting, exhilarating, etc. so it has a lot of draw to it. And many people won't dig deeper than the euphoric emotion that they feel. However, trading is MUCH harder than investing. And much of the industry is bent towards getting you to trade rather than invest.