The rules

Orchestral music should never be played in the afternoon. Romantic piano concertos are particularly depressing at that time.

Chamber music, string quartets, Lieder, etc, are particularly good in the evening.

Epic orchestral works are best appreciated around midnight.

Baroque music is an exception to the no-orchestral-music-between-midday-and-midnight rule. Mostly because it was written for orchestras before orchestras were invented.

In general, though, you should try to arrange for the day to be cold, rainy, or snowing when listening to baroque music.

Baroque music is especially good when it has viols. Make sure it has viols in it. Actually, everything is better with viols.

Ideally, the musicians should be there in the room with you.

There are solos, duets, trios, quartets, and quintets. Everything above has a technical name but is basically an orchestra.

If you can't fit them onto a rotunda there's probably too many.

English horns > oboes.
Oboes > bassoons.
Clarinets.... it's kind of a grey area.
Bassoons have unique comic value though.

There ought to be more music for hurdy-gurdies.

Orchestras should have both an English horn and a French horn. A car horn is right out.

Homophony is just polyphony in disguise.

Polyphony is just homophony in surprise.

Atonality is just tonality in wild surmise.

It is not clear when atonal music should be listened to. Please consult your doctor or pharmacist and take only as advised.

Except for Stravinsky, whose atonal music should be listened to frequently, in the early morning, while it is still fresh.