Long version
I'll let y'all in on a little "trade secret" of mine. In my first mechanic's class (Power Mechanics, just basic small engine repair, diagnostic, rebuild, etc..)
way back in the fall of '89, as a tall skinny 15 year old freshman in high school with skater bangs and a dirty jean jacket, after the first couple weeks of class work, then a couple weeks of shop time, the instructor would split the class up into half hour class time, half hour shop time. Except for class time you were on your own, you did whatever you had to do to prepare yourself for whatever it was you were going to be doing in the shop that day. Talk, study, research, whatever. He wouldn't even be in there. I'd always put my headphones on, and I found out after a while, that on Metallica's Master of Puppets cassette, if you stopped at the end of Sanitarium flipped it over and rewound for a few seconds you'd be at the beginning of The Thing That Should Not Be, and vice versa. They're both about 6:30, so if I flipped back and forth a few times, bam half hour, but more than that, it would get my head right, something about the rhythm, the tempo, the lyrics, the repetition it'd get my head right to think about what I needed to accomplish that day. It's almost meditative.
Short Version
If you listen to these two songs back to back to back to back to back, it's kinda trippy and around a half hour. (doesn't matter which one you listen to first)
https://www.youtube.com/watch?v=2pnS_7YsYzM
https://www.youtube.com/watch?v=BjxaM_2o9cw
https://www.youtube.com/watch?v=2pnS_7YsYzM
https://www.youtube.com/watch?v=BjxaM_2o9cw
https://www.youtube.com/watch?v=2pnS_7YsYzM