Great post and I agree.
About 4, 5 years ago I wasn't eating enough carbs in the morning and at lunch. This makes you feel like shit after training heavy. I felt very lethargic, moody and didn't feel well at all. Also, I wasn't taking in near enough protien, not like today. I thought I was overtraining then, but after reading more and changing my diet with vitamins and shakes, workouts are a lot better and endurance is longer. I actually feel like doing things after woking out now. Recovery seems easier also.
My 2 cents and Good post Senseial.