Right here. I have had every single version of the iPhone and this has caught me several times on iOS 7. It happens most when I have a song playing and the lock screen shows the album artwork. This change of context on the lock screen caused by the artwork display makes me react differently, and the visual queues have more influence than my normal lock-screen muscle-memory. Several times I have tried to either swipe up, or swipe left. The visual queues are definitely lacking here.
Another thing that really gets me is that when you have no notifications you can swipe anywhere on that screen to unlock. However, if you have any notifications then only the area directly at/around the "slide to unlock" works. If you have one notification it's the worst, because you have one notification at the top, a ton of blank area as normal, and then the slide to unlock. So in this instance you think you can swipe any of the blank area (as you can normally when there are no notifications), but you can't, nothing happens when you try.
Finally, I find the navigation/transition of the lock screen poor now. In iOS7 it is very clear in the transition what you are doing is sliding the entire lock screen to the right. So immediately after I unlock I feel very strongly that now the lock screen should be sitting there, just offscreen to the right. However, obviously when you slide left you don't end up back at the lock screen, instead you find your second page of apps.
So yeah... the lock screen has a ton of UI and UX problems.