It's debatable whether that should be the default or not; compare it to, say, printing diagnostic info by default and requiring a special `--download` option.

One thing I always change from the default behaviour is video quality: by default it wastes a ton of bandwidth and disk space getting "HD" versions. I can understand why that's the default, but I don't particularly care about resolution, as it's a pretty negligible contributor to quality compared to the actual content of the video.