No, it makes more sense than you think. It's not total sense, but it makes more sense than you think. It's just that since you don't seem to know what the terms mean you're getting a greater sense of confusion than is justified, plus technical people just can't resist the lure of trying to create bizarre exceptions which don't help.
What constitutes a single work is basically what a person on the street would answer is a single thing. What constitutes a collective work is basically what a person on the street would call a collective work, after they answer the first question. (That is, if you start here they might say an album is one work, but if you get them to agree that a song is one thing once they probably won't say that.) What constitutes copying is basically what a person on the street would agree is copying. That certainly isn't good enough advice to go off of if you're going to try to build a business off of it or something, and edge cases abound, but the core concepts aren't anywhere near as screwed up as you might think. The problem isn't conceptual with copyright, it is how the concepts are used and abused.