The magic moment is when you realize that your month of pain writing something complex saves the company years of writing the simpler version by hand. In the template a fixed bug is fixed once and for all. In the other version fixing a bug in once place doesn't mean anything about anything else.

Note that for the above to apply you need have a domain where there will be enough uses to make the generic version worth it.

Of course, just like it is fun to write code for the IOCCC, there is some perverse fun in writing complex templates.