My iPhone 3g had been sort of lagging when I access things. For example, when I went to phonebook, it took 3 or 4 seconds before I could select anything. Calendars and Mail also took quite a while. Even while playing game, sometimes things would randomly slow down for no clear reason (the games were not being particularly demanding with graphics/etc). Around that time, I noticed that PUSH was not working for me (it would NOT update with information put on the web). Because PUSH wasn't working, I turned it off. Viola. Now everything is back to being speedy. My phonebook is instantly accessible, I don't have lags in games, and the software is much better to use. I'm not sure if 1. PUSH just makes things slow, 2. if PUSH was messed up on my iPhone so it was slow, or 3. my iPhone is just acting crazy for other reasons. In any case, I thought the information might be useful for others. Maybe keeping track of this stuff will also help Apple improve their software (yes, I will report it).