I was trying to think back to the least useful chemistry I ever learned in undergraduate and graduate school, and let me tell you, it's a tough league to play in.
I know, I know, many of you are thinking "Yeah, I hated quantum mechanics, too", but that's not what I'm talking about. Quantum stuff is actually interesting to me, although I am glad to not be obligated to finish any paragraph that begins with "Consider the Hamiltonian. . ." No, I'm thinking of things that were presented as techniques that I'd be using and had better understand and commit to memory.
How about. . .electron spin resonance? ESR was sold to us as a parallel world to NMR, full of its own utility, well worth getting to know. Sheep dip. ESR is interesting and useful to that subset of people who deal with reasonably stable free radicals, but to very few others indeed. I take that point that it's a fine technique for those people, but I'd like to point out that my chances of becoming one of them were never very high. The time and effort I put into learning it could have been spent much more profitably.
"But hold it," says my memory. "You didn't spend any time getting to learn ESR spectroscopy. You read the newspaper during the lectures. You didn't buy the textbook. You only exerted yourself during the hours leading up to the exams, and sometimes not even then. It's no wonder you don't know squat about it."
Er, well, I suppose there's something to that. I recall that the class was divided up into groups of three or four, and assigned regular problem sets to work out and hand in. My group of three became increasingly demotivated as things went on, and by the time of the last problem set, we spent our time complaining about how much we couldn't stand the stuff any more and never got around to solving any of the problems.
Come that Monday morning, I realized that I hadn't put anything together for us to hand in. So I just dug around and found a sheet or two where we'd taken a listless stab at working a problem. That seemed a bit lacking in heft, so I bulked it out with a random handful of paper from a disused notebook, put our names on it, stapled the pile up, and turned it in. There were blank sheets of paper in there; there was a paper towel. The sheets with writing on them often weren't even from the course in question, and many of them were upside down, anyway. What the hey.
Looking back, it's hard to believe I actually did that. My problem set partners found it a bit difficult, too, even at the time: "You did what?" I awaited our grade with interest. A few days later, the professor stopped me on my way out of the class and asked "Do I have your group's problem set?" "Sort of," I responded. "Oh, yes!" came his answer, "that was a messy one, wasn't it?"