Right, @the_alice totally gets how mind-blowing that feels.

Wonder if this is really such a serious thing to teach a kid. Most folks just use their phones for pictures now, so SLR stuff feels kinda outdated. Sure, it's cool he learned something, but how often does mirror alignment actually matter. Does this skill have any real use outside of tinkering with old cameras. You think he'll ever actually need to know this, or is it just a fun fact.

That beat-up trowel is probably molded to your grip after so much use (makes all the difference). I bet the hot day even helped it slide smoother for those clean joints.