Naturalness part 2
Contour Bias - people prefer flowing, curved structures instead of straight line and angle structures
Curved surfaces connote safety, angled or hard edges, danger
Animation - misused more often than not. Used to draw attention to things, which is usually irritating. Like gradients, animations should be unobtrusive and work in harmony with what the brain and visual system expects.
Fade things in and out instead of having them blink in or out. Indicators should fade in and out as well (4/10ths of a second to fade is a good starting time)
Animations can help maintain context i.e. having something shrink and fade to the background instead of having it blink there.
Users prefer a 3D experience as opposed to a flat one - the real world is 3D. Shapes, shadows, layering, reflections, perspective, texture gradients, atmospheric perspective.
Aesthetics and Usability
A beautiful design is considered more usable. Users will give a "beautiful" app more chances than an "ugly" one.
Don't spend much time on typefaces for business apps, almost all modern default fonts are fine.
Keep number of sizes used to 3 or 4 (what about different font faces?)
Legibility is affected by size, contrast, and spacing
Allow users to change the font size and have your application adapt