This one's short but sweet. Adapted from a comment I left on David Pogue's blog:
When I press a button on my Sony Ericcson, it takes almost a second to pull up the menu. It’s like working a phone underwater. I wish the UI designers would take a second to try to figure out how to optimize their phone’s response time to the hardware they’re going to use it on. It’s not hard people - Apple seems to know how.
The best UI I’ve ever seen on a phone is Nokia. Simple, direct and fast. My next phone is definitely a nokia.