Tbh I know many hobbyists (carpentry, mechanics, home improvement, gardening, etc...) who take their shit soooo seriously, they outdo professional contractors... but then again they are the exception. The reason for this is that:
a) they are completely anal / OCD about it, and/or;
b) they are passionate about it, so their passion tends to shine through in the end results...
A hobbyist has the ability to spend weeks or months on a single project, while professionals are expected to churn out multiple projects/clients/etc every few days. Professionals also often have some sort of certification/licensure that is guaranteeing their work.
a) they are completely anal / OCD about it, and/or;
b) they are passionate about it, so their passion tends to shine through in the end results...