When the folder WordPress is installed in has restrictive file permissions (no read nor write), WP CLI fails with a non-helpful error message.

pippin@pippin-XPS-13-9360:~/sites/wp$ wp plugin list
Error: This does not seem to be a WordPress install.
Pass --path=`path/to/wordpress` or run `wp core download`.

The error gives the impression that the wp command is being run from the wrong folder, when in reality it's the correct folder that just lacks the proper permissions / ownership for the user running the command.

It would save a lot of debugging time and trouble if a meaningful error message was returned.