Invisible Details of Interaction Design

What makes great interactions feel right?

Jul 17, 2023· 16 min readUpdated Jul 27, 2026

Design can feel like there's no science to it—only feel and intuition. Even researchers have trouble grounding interaction design practices in science, inherently treating them as a mysterious black box. While from my own experience that's partly true, I have been trying to deconstruct and excavate the why behind great displays of interaction design.

The essence of the word "interaction" implies a relationship between a human and an environment. In my experience, great revelations surface from making something—filling your headspace with a problem—and then going for a synthesizing daydreaming walk to stir the pot.

This writing is neither a tutorial nor a collection of guidelines, but rather an observation of the invisible details of a few interactions that I use often but rarely think about. Besides recreating interfaces, I found this exercise in reflection to be another great way to build a stronger design intuition and vocabulary.

Metaphors in interaction design

Interaction design is an art form to make experiences that fluidly respond to human intent. When does a swipe trigger an action? Do gestures retain momentum? What happens if a finger is covering content? How can we predict intent based on context? Executing well on details like these makes products feel like a natural extension of ourselves.

But it's not an art form in the same way as painting or composing music. There's a unique human component to interaction design. Why? Because ultimately people are trying to get stuff done using a product. Beauty in form and composition is not enough. There's an inherent satisfaction apparent in striking a holistic balance between form and function.

Great interaction design rewards learning by reusing metaphors. You can use most touch interfaces with just two gestures: tapping and swiping. For example, on iOS the only gesture you're explicitly taught how to do is swiping up to open: