Is quantum mechanics "rational"?

Quantum mechanics seems weird to everyone.
Some people look to that weirdness for supporting weird hypotheses that don't much fit with day-to-day observations.
Most physicists reject those weird hypotheses and seek to reconcile quantum mechanics with the entire body of human observations.

The abstract of the first article in the Aug 1999 issue of Physics Today reads:
"The traditional Copenhagen orthodoxy saddles quantum theory with embarrassments like Schrödingerís cat and the claim that properties don't exist until you measure them.  The consistent-histories approach seeks a sensible remedy."

The following is extracted from our
Misconceptions Workshop:

Certain statements give little clues that something wasn't really quite understood.

...simple, but subtle...
...obvious, yet unobserved...
...the edges of (easy) human comprehension..

For the following:
We should like to know:
What are the clues?
What was missed?

How might it affect important decisions?