Before getting into Euphoria, it's always a good idea to perform a thorough reality check. The stock market will go up to a point before the reality kicks in, whether you like it or not. YMYD
1. Buffet Indicator: https://www.longtermtrends.net/market-cap-to-gdp-the-buffett-indicator/
2. Shiller PE Ratio: https://www.longtermtrends.net/sp500-price-earnings-shiller-pe-ratio/