So if you trade by emotions you will very likely loose money on the longterm. Therefore you should try to stick to your strategy and use as much technical tools for chart analysis to avoid trades lead by emotions
Traders who are extremely emotional do not apply TA at all before buying a coin. If for example you analyze properly, you should know where to set your stop limit (stop loss) and sell order. What I normally do is, after buying a coin, I set sell order and SL using OCO incase the market goes south.
Using stop loss or no is subjective and every trader has a different set of rules in trading, especially for volatile global markets trading without SL can lead to stop out or margin call. Precaution is mandatory in such cases and using take profit orders will guarantee the profit at the end of the trade.