and I often laugh when I see people buying crypto when the price is going up,
I also laughed at reading this, if everyone has thoughts like you, how did bitcoin in your opinion at that time touch the "high price"? Bitcoin went up due to buying action everywhere. You're not completely eliminating the risk of losses even if you bought at a low price (from your perspective). So I'dn't gonna laugh at anyone buying bitcoins in any market situation.
The OP here is basically invoking an asset to buy from the dip. He believes that one should buy when the price of a coin is going down and stop when the price of that coin is going up. These words are very familiar among investors. Every investor may be well aware of these factors but sometimes the erratic behavior of the market makes it difficult to make quick decisions. Because the crypto market is volatile and when the market is bullish, the price of almost all coins increases at a huge rate and how sustainable that increase which is unknown to everyone. If everyone knew then they would neither buy high nor sell low. It mainly depends on the market situation.