Have you updated to iOS 9 yet? If so, you may be living in the future, and I don't mean in the sense of being an early adopter. Your iPhone's system clock may actually be set forward 5 seconds or more.
To check, go here and select your timezone. Then hold your iPhone up to the screen. Take a look at the icon for your iPhone's Clock app. Conveniently, you can directly compare the animated red second hand on the Clock app icon with the animated red second hand on the World Clock website. Notice any difference?
Here's what this looked like for me three days ago when I updated to iOS9:
As you can see, the clock on my Verizon iPhone 5s is running ~8 seconds fast. I've tried restarting the phone, among other things, and I haven't been able to get an accurate clock no matter what I do. And, yes, my timezone and clock are set to auto. In fact, as of today, the problem has only gotten worse. My phone's clock is now running more than 15 seconds fast!
This may not seem like a big deal to you, but for me, it is. I'm one of the founders of Streak Trivia. Streak is a massively-multiplayer trivia game that everyone plays simultaneously at 6PM PT / 9PM ET. For our game to work properly, it is imperative that we can trust Apple's system clock to be set to the correct time. Any slight deviation of more than a second means that our players are not synced up, which means they aren't receiving questions at the same time.
The problem doesn't impact every phone upgraded to iOS 9. We did extensive testing on iOS 9 beta builds and never encountered the problem until a few days ago. My co-founder has an iPhone 6 Plus that has not been impacted to-date. However, the issue seems fairly widespread. Last Friday about ~10% of our game players were affected (meaning they couldn't play Streak because their clock was wrong). As more and more Streak players upgrade to iOS 9, the number of people who can't play is growing. In fact, we've had to cancel all of our games this week to keep users from encountering clock-related errors, meaning our app has been forced into dormancy by this bug.
In computer programming, system clocks are pretty darn important. If the bug is affecting millions of iPhones, then computer clocks probably haven't been wrong on such a grand scale at any other point in history. This issue is almost certainly causing problems in other apps besides Streak, or at the very least, robbing average users of a few seconds of precious sleep.
Are you living in the future?