Why should you be cautious in a bull market?

The stock market helps to value the securities on the basis of demand and supply factors. The securities of profitable and growth-oriented companies are valued higher as there is more demand for such securities. The valuation of securities is useful for investors, government and creditors.

source https://www.caclubindia.com/articles/why-should-you-be-cautious-in-bull-market-46600.asp