@GlowingLantern you’re right. Solid UX design and interaction design of all sorts build on, accommodate and really only thrive when the knowledge, experiences, cultural realities and more of the people using it are taken into account.

A round door knob is intuitive once one is shown but only if one is not differently limbed. However, a door handle (like pictured) even some animals may be able to figure out with no instruction or example.