You should always know your tolerance level. Risk management is the key to successful trading. So this is very vital for that purpose. When you enter a trade, you know what level to exit. Either by lock in profit or cut loss. Practice that and you'll know the difference.
Majority of the people dont understand risk management at all. They come in to make money and hope for huge returns on small investments then they complain about it and cry that it was a scam. I am surprised by the mentality of these people. Its speculative trading and they call it scam when there was no scam at all. Either they dont understand how market works or how a scam works. 
Seeing a loss on part of the price gets their pants in a twist since they bought in at a high price. Its an obvious thing but its also important to learn how to be patient when prices drop like this.