One mistake clients make is the all or nothing mind-set. Many people have are full of good intentions and they want to 100% perfect with training and nutrition. If these people with all or nothing mentality miss a day or two of training or go on a bag of chips pig out , they think they failed completely and get all dejected. I tell my clients use the 80-20% rule. It's okay to have an extra glass of wine a few chips a carb (omg) and enjoy it. It's ok to take a day off training. Stick to the 80% rule of staying on your training and eating plan and you will be successful.