Why a 50 mm lens (or an equivalent) makes pictures look so good

I bought a used Panasonic Leica 25 mm f/1.4 lens recently. This is a micro four thirds lens with the 50 mm full frame equivalent field of view and a wide aperture. Even if I previously owned the Panasonic 20 mm f/1.7 lens (40 mm full frame equivalent), it never enthused me as much as the 25 mm. One thing...