In life we all have some good days and some bad days and no matter how much we try there is no way we can avoid the bad ones. Since that is the case, why stress out over them and drag them along. We should accept them for what they are and simply move on. Instead of saying something like "Darn it another bad day, it seems like nothing is going right in my life". We should try and change that negative energy into thoughts like "well, everyday can't be the best, but now that I've gotten this bad one out the way I know tomorrow will be good". It's sort of like the rule of probabilities. No matter how many times you flip a coin, there is always a 50/50 chance of you landing on heads. With that being said the more it lands on tails, simply means that the chance of it landing on heads next is increasing.
Every day you have a 50/50 chance of either having a good day or a bad day. So if you have a bad day today, forget about it and look forward to having a good one tomorrow. An important lesson I learned while training to be an investor was "Cut your losses short, and let your winners ride". Consider your losses to be your bad days, and your winners to be your good ones. That's how you become profitable in the long-run.