What professional astronomers know about telescopes (often, not much!)

Yours truly at Kitt Peak in 2002 (I think).

Most people assume that we astronomers know everything there is to know about telescopes.  After all, we use giant ones for much of our work!  So it shouldn't be surprising that one of the most common questions we get asked (after the black holes and aliens have been addressed) is something like: "I've been thinking about getting a telescope.  What should I get?"

Many of these people are then quite disappointed to find out that I cannot help them much.  Sure, I give them the standard (and excellent, IMHO) advice that they should avoid $49 specials at Walmart, start with binoculars and then, if still interested, progress to something like an Astroscan. (Full disclosure - I own an Astroscan and love it, but I don't get any compensation whatsoever to talk them up).

But if you ask me which is better: a Celestron NexStar or an Orion StarMax, and I will give you a blank star.  I have no clue.  Or if you ask me why your iOptron SmartStar Maksutov has this weird coma when you put a certain filter in but not with a different filter by the same manufacturer, and I'll only be able to blurt out the obvious "maybe there is something wrong with the filter?"