I'd suggest that your "best" work is a funcion of what you are trying to
accomplish. "Best" for a piece of furniture you expect to last for 200
years is quite different than "best" for having fun making curlies from
a branch off the firewood pile. The objective in each case is quite
different, therefor what comprises "best work" has to change as well.
The "best" quick and dirty patch is one that is accomplished the most
quickly and cheaply that accomplishes the task. Spending hours out in
the storm to make an elegantly crafted, perfectly fit patch for the hole
in the wall is a pretty perverted idea of best when the rain is coming
in the house! Similarly painstaking attention to detail may not
accomplish either the fun or learning goals of playing with making
shavings out of firewood.

Yes, I think one should always strive for "best", but the definition of
best has to be made appropriate to the task at hand--are you
accomplishing the goal in an optimal way, be that making the most
perfect object you can, or having the most fun possible, or whatever
blend you have set for yourself that day.

Roger