Eat a Frog in the Morning
Eat a live frog every morning, and nothing worse will happen to you the rest of the day”
- Mark Twain
It is not easy to find a live frog to eat every morning (thankfully!), but there will always be unpleasant things (and waaaay more beneficial) to do that will make the rest of your day less ‘bad’.
Take exercise. It used to be a daily morning ritual, until I had to move house; it's certainly unpleasant to be awake at 6.30am, especially if you had a late night out, and be working out while you're groggy and sleepy. But, it does make your social life a little easier than having to go work out in the evening.
As an advice, it does not translate to everyday work. Not all days have unpleasant work and some work can span across days. For me, mornings are also times when I have the best focus - it has to be spent on important work, not things that I wouldn't want to do.
Some gurus promote this as a productivity life hack; I wouldn't say this can practically be done daily for all forms of work, or would have the efficacy that can be applied on a consistent, daily basis.