Hold your stocksssss

I recently got into stock trading and my dad was overjoyed that I was interested in trading and told me about how once, when he had invested in the Indian real estate market, it had crashed and he had foolishly taken out all his money. Even now he regrets doing that because the collapse was temporary and soon the market was at new highs. His No.1 advice to me was never panic sell, always hold to see what happens.