Other subjects are the same, obviously, but when writing a history essay you can BS and not think too hard and skate by with a C. With a math problem, if it's difficult for you, you need to really put your whole self into solving it to make any progress at all. And I think that can be painful, in a certain way.
That discrepancy between the goal (photorealism, or at least beauty) and the result (ugly art) is very painful for me, to such a degree that it discouraged me from putting much effort into art, despite my love for it.
I would say that in the kind of math you study after calculus it becomes more common to have that "I know what the solution should look like but I can't seem to get there" feeling.
This isn't to say give up on photorealistic drawing: but don't bludgeon yourself with it. If you don't find it fun, you're probably not at a point where practice will make perfect.
