You say that, but you probably do care at least a little.
It benefits you when an application doesn't do surprising things. Even basic things like clicking in an edit control, it's better for you if that results in the same outcome across all apps (stuff like does it select all text? does it place the caret at the end?).
Even for command line apps, consistency is good (see https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1...). Are options specified with a hyphen? Two hyphens? A slash? Are lists delimited with comma or semi-colon or something else?
