Let's face it; by and large math is not easy, but that's what makes it so rewarding when you conquer a problem, and reach new heights of understanding. ↗
As far as modern writing is concerned, it is rarely rewarding to translate it, although it might be easy. Translation is very much like copying paintings. ↗
An athlete who tells you the training is always easy and always fun simply hasn't been there. Goals can be elusive which makes the difficult journey all the more rewarding. ↗
I don't hate work, composing is not work for me, it's my pleasure; it's my life. So why should I stop? If something is pleasurable and exciting and rewarding, why should one stop? ↗