I assumed too much

Many people make fun of assumptions.   The whole "Ass-You-Me in Assume" thing.  They probably don't know how often mathematicians, scientists and engineers make assumptions every day.  And the professional "assumers" are wrong too; but it's just amazing how much you learn when (after) you're wrong about something.  The individuals who aren't too heavily stapled to their hypotheses, theories, or preconceived notions so not to collapse their careers are the ones who ultimately thrive.  
This, it would seem to me, lends itself not to avoiding assumptions in the first place, but to never stop making new ones in the last place.   It should work just as well for the masses as it does for the labcoats, hardhats, and pencil protectors.  If you're afraid of being wrong, don't assume anything.  If you're not afraid of proving what's right, let it rip.x