January Meme: Companions and Doctors: what makes particular combinations work for me

Necesssary preamble: all of this is extremely subjective. What looks like a good arc for me doesn't have to look like one for you, ditto for chemistry being in the eye of the beholder, etc. And nothing is meant as a disparagement of your own favourites, choices, etc.

( Vague spoilers for both DW tv series and Big Finish audios )

The other days