iTunes playlists not playing continuously

Also, this:

I had a problem with having iTunes 12 play Audible.com files continuously. I tried hitting play on the first one and it would play it and stop when it hit the end of the file.

Then I tried with a playlist. Same thing.

After much fruitless Internet searching. I started looking at the options for each file in the iTunes window (a lot of right clicking was involved). Finally I clicked the "Check Selection" on the context menu for all the files in my playlist and Bingo!

Essentially, you can select a bunch of files, right click on one of them, and then create a playlist on the fly with your selection. But once you create a playlist with non-music files, playback stops after each file - unless - you specifically tell it that you want them all to play. I wanna know: who at Apple decided that.