Our fitness and training is tied to our overall life. If you really look for it there are other areas in your life that if you let slide, good chance your training is sliding as well. For me it is hair cuts!
When my hair starts to get too long and I start wearing a hat everyday I am probably letting some things in my training and diet slide as well. For me it is totally a confidence thing. A fresh haircut and beard trim makes me feel confident and energetic. Believe it or not this bleeds over into all aspects of my life including my training sessions.
If I feel so good with a nice haircut, why do I let it slide? Just like everyone else will answer, life. I get too busy at work, I prioritize other things, I drive by the barber and see a line and don't feel like waiting. I really need to stop putting off things like this that carry over into the rest of my life so that is a big goal right now!
Find the thing that makes you confident and stay on top of it! Your life will thank you.