Jeff Grossman asks:

>what is it that makes a good conductor?

Outstanding general musicianship, thorough command of the score, and
ability to communicate musical signals clearly, for a start.

>Why do some conductors have the ability to immediately connect
>with an audience or orchestra, and others immediately turn us away?

If the players are not convinced the conductor has what it takes they won't
play their best and may even undermine the performance.  The audiences I've
known respond to what they hear (rather than flashy manners, say.)

>Is it necessary to be somewhat of a tyrant to be a good conductor?

No. Leadership is what is needed, and that does not call for
authoritarianism.

>Must one play every instrument well, or is it only necessary to have
>working knowledge of all instruments?

The latter.  The former is impossible.

>And how does the level of orchestra influence this standard?

Any ensemble will play better with an outstandingly good conductor.  What
you need is to get the players to want to do their best, and that will
happen in an atmosphere of mutual respect.

>When you hear an orchestra that sounds particularly good or bad, do you
>think the conductor gets the credit for it? All the credit, or just some?

Quite a lot, but I know one orchestra so bad that I'm not sure any
conductor could make it sound really good, but such remarks as, "________,
your playing is a public disgrace," from the conductor in rehearsal
probably didn't help.  At the other extreme, the Boston Symphony Orchestra,
even after many years of the much maligned Ozawa, is still capable of
playing outstandingly, so either Ozawa is better than some give him credit
for, or sheer professionalism and the tradition of the group have survived
on their own.

Jim Tobin