Well then you save all of your difficult classes towards the end and have to take them all at once. I think it’s better for difficulty management to balance your schedule so you have a mix of difficult and easy classes, or what you perceive to be difficult and easy - because classes often turn out different than you expect. The most challenging classes I took in college were NOT math or science classes; they were French 202, an honors philosophy class, and an upper-level Japanese sociology course. Frankly I find math and science to be kind of easy to learn; I have much more difficulty with abstract and theoretical concepts. Which exemplifies another concept, that things that are difficult for some might be easy for others and vice versa.
That said, psychology 101 does have a reputation of being easy for most students, but it also depends on how it is taught. At my undergrad intro psychology was a two-semester sequence; pacing was good, the classes were split pretty equally between the more biological aspects of psychology and the social/developmental ones, and I found the class to be pretty easy. At my grad school, I TA’ed for intro psychology and it was significantly harder IMO. It was only one semester, and the class was probably about 2/3 biological/cognitive psychology. More memorization and systems testing than anything else. Assessment was also different - I went to an LAC so the final paper was weighted more heavily than the tests. I TA’ed at a larger research university and the grades were heavily reliant on performance on primarily multiple-choice tests, which were more about fact recall.