I did it at an amateur level many years before depending on it to pay my mortgage. When you do it for a living it's very different. You no longer strive for perfection, you strive for expectations management.
Some things cannot be perfect due to prior imperfect work. For example if a room isn't square, or something isn't level, you build your new work to match previous errors or your work looks out of place.
I walk onto a jobsite and there are some unspoken rules. Learning these rules is part of the fun. At the end of the day it's just a bunch of people trying to get something done.
Working in trade also helps you accept the principle of "good enough". You should always try your best, never give up, but accept things aren't perfect. What you see as imperfect will likely never be noticed by the property owner.
Dealing with the customer has some quirks too. If you run a bundle of cat6 that looks like laminar flow then you will blow their socks off. They assume everything else is perfect. Meanwhile you could have wrapped cat6 around a/c ducts 10 times in the attic and they will never know.
Knowing where to put your effort is an art.