Every time I realize I'm guessing about (rather than directly seeing) the behavior of my code I think of Bret's talks. I never actually improve my workflow, but at least now I'm angry about it!
I think debuggers are under appreciated by Open Source languages(as in, it's not THE priority). An approach I am forced to use is heavy log statements and a DEBUG flag, so that I can feel the program show me what it's upto.
I think Bret's ideas are worth pondering on. The only issue when dealing with the philosophical idea of time, I find for myself, is that it's an easy rabbit hole to fall into.
Nice interesting paper tangentially related to this, http://www.vpri.org/pdf/tr2011001_final_worlds.pdf