Friction exists to make us notice what we’re doing. [...] Bad friction is friction without purpose. It exists by accident, or through neglect. It asks more from the user without offering anything in return. [...] Good friction is different. It’s intentional. It’s added with a clear reason, and it earns its place in the experience — often through utility.

Good frictions:

• Holding ⌘Q to quit a browser session is a deliberate pause before closing everything
• A brief delay after sending an email, allowing you to undo before it’s final
• Intentional pagination instead of infinite scrolling is progress with awareness
• A warning when an email mentions an attachment but none is included is a small check before sending