Stop loss can frustrate you sometime but it is definitely a life saver. Sometimes it happens that after eating your SL market move in the same direction you wanted but manytimes it happens that if you do not put a SL, market keeps on moving in the opposite direction untill it eats your account, so accepting small loss is always better than to risk the whole account. The best way to keep SL is few pips away from swing high or swing low. I hope it helps.