(2) Making it through the worst bottleneck in civilization, bad documentation of computer hard/software, and then getting my software that uses that hard/software to work.
(3) A new, really good performance of some of the best music of the top few classical music composers, Bach, Mozart, Beethoven, Chopin, Wagner, Puccini, Verdi, Tchaikovsky.
I would list proving a new theorem or making a successful application of some theorems, but that pleasure was ruined for me: I had a good background in math (career, independent study, college) and computing (career) both a good career and a good marriage going, and my wife, brilliant, PBK, etc., and I decided to go to a famous research university and each get a Ph.D. When we left I had been in a multi-year, highly threatening, bitter, no holds barred bar fight with lots of jealous professors. That I (a) by far led the class in the department Chair's flunk-out, filter course, (b) did the best in the class on 4 of the 5 qualifying exams (c) in two weeks independently did surprising, publishable research (later published), and (d) had good progress on my dissertation research when I arrived and easily, quickly completed the research independently all just made the fighting more bitter. It appears that the fighting caused 5 of the professors, including the department Chair, to be fired. And there were at least 3 more profs fighting me. One of the profs, famous, I happened to meet some years later, and he still wanted to fight with me. My wife was treated poorly, for the first time in her life of a brilliant, spotless academic record, and the stress put her into a depression and a clinical depression that proved fatal. When we got our Ph.D. degrees and left, my career was junk, my marriage was junk, my finances were ruined, and my wife was fatally injured. Three profs tried to be nice to me, and two of them taught me some good things, but nearly all the rest of the profs I knew just tried to destroy me. And one of my wife's profs tried to destroy her. So, tough for me to get much pleasure out of research or applications of math. Weekly the university sends me requests to send them money -- HA!!!!
Solution: Take advantage of the current fantastic, historic opportunities of computing and the Internet to pick a niche problem, find a best solution for the niche, write some code, do a startup, solve the problem. So, sole, solo founder, 100% owner, with no teachers, profs, managers, BoD, or investors over me. Users interact with my Web site and nearly never with me. Revenue? Run ads I get from ad networks, etc. One more instance of revenge of the nerds!