Your app makes me fat — Serious Pony:
If your app is confusing and your tech support / FAQ isn’t helpful, you’re drawing down my scarce, precious, cognitive resources. If your app behaves counter-intuitively – even just once – I’ll leak cog resources every time I use it, forever, wondering, "wait, did that do what I expected?". Or let’s say your app is super easy to use, but designed and tuned for persuasive brain hacks ("nudges", gamification, behavioral tricks, etc.) to keep me "engaged" for your benefit, not mine (lookin’ at you, Zynga)… you’ve still drained my cognitive resources.