Well, it wasn't always agonizing, but it was interminable. I finally, finally finished the Teaching Company lectures on the history of Russia from Peter the Great through Gorbachev. I did learn a lot, but it spent way, way too much time on the intellectual history for my taste. I did also learn that if I had to pick a century to be a Russian, the only good option is "the next one" because it manages, amazingly, to never get better, and to repeatedly get worse in a historically unprecedented fashion. (That's not strictly true - things appear to have improved from Russians from the death of Stalin on, and markedly in recent years, but there's never been the sort of upward leaps and bounds that students of American history are used to. We may have unbalanced growth and improvement, but at numerous places in our history there has been a rising tide that lifted almost everyone at least some. There are few - if any - such periods in Russian history. And on top of that, repeated policy disasters (and sometimes simple genocide) that killed millions and sometimes tens of millions. We have frequently sent soldiers into battle with outdated equipment, but we never sent a column of soldiers into battle and told them to pick up the rifle when everyone in front of you gets shot. At Midway, at least everyone in Torpedo Eight has an airplane, obsolete though it was.
As a student of World War II history, I do need reminding that for everything the U.S. did in the war, Russia did it with an invasion on its own soil, with no officer corps when the war started (because Stalin had purged them all) and not much of an industrial base or economy as a whole to produce the war material it needed. Russia lost millions upon millions upon millions of soldiers and civilians and fought on - it's no wonder than Stalin was emphatic with Roosevelt and Churchill that he needed a second front and it needed it last week.
The only good part is that it was more interesting than the other option on my iPod, which is the history of American intellectual thought, which at the moment is arcane, blinding dull theological disputes between Puritan ministers in New England in the 1600s.
I am now trying to be a little more disciplined about how I do these, and finish one before starting another. I couldn't stand it and had to break open a new one on the Old Testament the other night because I was sick to death of Roman monuments, but I'll eventually get that one polished off (and I am learning a great deal in the Roman one, dull as it sometimes gets).