Risk on a trade is a common one.You have to learn things from the loss trading.In a gain trading, you can't learn anything. But while thinking on a loss alone, you get the same as a emotional one. It may leads to the sad mood.I had loss over 3500$ in a future trading of two big trade. But I had get into the idea of next trade. Because I had a strong mind to get all my loss to my own wallet. The positive mind is the only source for the next trade after a loss.
That's a lot of money that's hard to lose. Future's isn't for everyone but if you've managed to recover that eventually then you're a great trader I should say.
Not everyone that losses that amount are easy to recover it the next trade that they have. It is true that positive thinking will help you but not all the time when you're over optimistic.