Waking up in the morning is a great struggle for many people, and it can make these people rather grouchy throughout the day if they have to get up out of bed early. I myself struggle on occasions and think how on earth do I manage to get up on these days. So I started exercising in the morning, instead of later on through the day. It honestly feels so much better, personally I find it a great start to the day. Exercising in the morning will increase happiness and reduce the fatigue of the mornings. Even if it is only 10 minutes worth of exercise I still find it helps a helluva lot, especially to reduce sleep eyes in the morning. The other advantage of doing exercise of a morning is that you aren't as exhausted as if you were attempting exercising after a tiring day out at work/educational places. I personally don't attend a gym to do my exercising so it is a lot easier for me just to roll out of bed and workout (sometimes I will exercise in my pyjamas it's just that easy, but the effects are still amazing). I have noticed a difference in how I approached each day when I exercised in the morning compared to when I did not, and the days when I did exercise in the morning were a lot more positive.
Even if you don't do this all the time, I would definitely recommend trying it at least one day and see how it goes (you will not regret!).