You are not at loss until you sell anything so it's not like there is no opportunity when the market goes the other way but it's just the emotions take control over their decisions and create a panic sell situation which is the main reason they lose even when they are not supposed to do. But with altcoins the situation can be tricky, it can go all the way to zero and there will not be coming back so just invest as little as possible and never go all in no matter how sure you are about the project.
Not closing the trade might just maximize the losses as prices might continue going in opposite directions. This will just make things worst if you are not well prepared to hold your trades for a longer time.
Watching the markets closely at such situations is really important but yes, we also need a lot of patience in order to not panic sell and maintain the positions in case of a fake out.
Not every position will show us profit. Initially they will start showing loss and that is when emotions will come into picture. Most will start losing hope and think about closing their positions. Once they close the positions, the markets will recover and it will just create regret and FOMO just enough to enter the trade again at a very hiked price.
Almost everyone might have experienced this but what changes our mindset is a proper risk management and patience. You need to throw away the greed and be as patient as possible because things will get better if you trust your trading strategies.