When you set your stop loss too tight, meaning only 10 or 15 pips, the market can easily reach it. I have a bad experience with a tight stop loss so I set a stop at 20 to 30 pips because it will take time to be hit by the market unless an abnormal spike occurs. and Since the average market volatility for major pairs is around 100 pips, maybe 20 pips is enough because it is already 20% of the daily market volatility. When it reaches stop loss, it means our prediction is missed and we don't need to suffer more losses.