When studying elec. eng. what do you think is rougher? Grad courses, or undergrad?

Someone studying electrical engineering, was talking about how their undergrad seemed kind of rough in general, like a lot of studying is what they probably meant, so on and so forth, QUESTION: Is it normal for electrical engineering for the undergrad to be "rougher" than the graduate classes? That's weird, or is it not weird? And what do you think they probably meant by graduate vs. undergrad anyways? Maybe they were just meaning their prep courses for their major?