If you believe most productivity experts, the answer is probably frogs.
The term "frog eating" originally comes from a book by Brian Tracy called Eat That Frog, where he defines a "frog" as any difficult or unpleasant task. Tracy recommends "eating a live frog" first thing in the morning so that the rest of the day is easy in comparison.
Initially, this concept made sense to me. I could finish the task I’d been dreading while I still had a full day’s energy: no more procrastination, no more worries. [...]