Some folks have said that Murphy, the author of Murphy's Law, was an optimist but he was probably just a riflebuilder!
Seriously, the one rule that makes the whole building process more efficient and therefore easier to enjoy is "Do not spend time working on wood or metal that will not be part of the finished rifle." I am amazed at how often a builder will be carefully rasping, filing, or chiseling on wood that is a quarter of an inch or more above the eventual finished surface. This applies to barrel inletting, stock shaping. and even small tasks like cutting the cavity in a patch box. It does not need to be smooth until all the extra wood is gone! I try to always use the coarsest file and biggest chisel that I can control for each step.
Gary