It was pay by the hour. No, the main motivation was being able to feel like I reliably accomplished something each day and hung out with a nice group of guys throughout the process. Hard work, visceral daily achievement, and camaraderie. The physical work was a part of it, but I wouldn't say it was the core thing.

Thanks for replying me. Did you have autonomy (like did you feel you could execute your job in the way you think it was right)? Did you have a mission (the feeling that your job was part of something bigger) ?

Nope and nope. Just clear instructions, clear tasks, and clear outcomes. Monotonous work and no sense of vision at all. No sense of responsibility either.