Absolutely. That happens to me no matter what workouts I miss. A doctor friend once told me its endorphin addiction.

I definately feel that! Running gives me a lot of time to think, reflect, and solve problems in my head -- which makes me much more focused and ready to take action. I've also noticed that running is the best thing at the end of a bad/long day. It gives me energy and powers me out of that bad mood into the "I AM POWERFUL" mindset.

I DEFINITELY am in a better mental state (better mood) when I work out than when I don't.  I had always heard that exercise would improve your mood, but I I noticed one particular example that absolutely proved it to ME personally.

A few weeks after I began my exercise regimen last spring, I noticed that I was singing with the radio on the way to work.  I USED to sing with the radio all the time, but I suddenly realized that for some time (maybe years) I had not sung with the radio.  The ONLY change in my life at that point was the addition of exercise to my daily routine.

I slip into a mild lethargy when I don't run. It is my boost and my relaxation. I am a much better person, happier, more productive and energetic.