What are common UI/UX mistakes that reduce website performance?

Common UI/UX mistakes that reduce performance include: low-contrast text that fails accessibility checks, navigation menus with too many options that create decision paralysis, CTAs that blend into the background rather than standing out through color contrast and sizing, and forms with excessive fields that increase abandonment rates.

On the UX side, frequent failures include designing for assumed user behavior rather than tested behavior, building page flows that require too many steps before reaching the conversion point, and neglecting mobile UX in favor of desktop-first layouts. Tools like Hotjar reveal where users drop off and what they click versus scroll past, providing actionable evidence to fix these issues through targeted design iterations rather than full redesigns.