I learnt my work ethic in the military during conscript year. We had this shitty lieutenant who kept saying that military was "all about attitude". I don't think there is a direct English translation for this use, but the meaning was your attitude towards doing tasks. In the military these tasks were of course the most elementary, repetitive and tedious task you could imagine. His definition of "attitude" was to complete these tasks as thoroughly when alone, as if the lieutenant was watching the whole time.

He was a shitty guy, military was a pretty bad year, but the attitude part is something I brought with me into other jobs. If you got 10 minutes alone to relax, go get a broom, bring out the garbage. Made a mistake working? Clean it up 100%, even if noone saw what you did.

Some time later I had my first seasonal job. It was a basic job in retail. After a while you get bored on the job, you get annoyed by the costumers, maybe you're running late a few days. Basically you are showing up to get paid, that is it.

My plan was to start school, but I ended up being unemployed instead. It is not before you have lost something, you appreciate you what you had. I couldn't get a new job in retail, even with my experience.

Almost half a year later someone finally gave me a chance through a vacancy agency. After that I changed my view on showing up for work. I try to do my best all the time, and I try to give 105% when the job asks for 100%. I am ready 5 minutes before my shift starts and I work 10 minutes after my shift has ended if it's needed. When my leader goes in to check on the crews hours, they see some people showing up late and leaving early, and a few others who give the little extra every day.

TL:DR: Work ethics can come from many places, I got mine from the military and being unemployed for some time.