Every day when watching content of one variety or another I experience A/V sync problems. Sometimes the audio gets ahead of the video, sometimes it lags behind.
I know the root of the problem is that the audio and video content take drastically different paths from the source to the viewer's eyes and ears. Different processing and transmission steps introduce different amounts of latency. Syncing that stuff up is a difficult problem, but not an unsolvable one. Why does it manifest itself so frequently? Is it a failing of the various standards that don't allow the various components to talk to each other and work out their various latencies? Or is it just poor/lazy engineering? I wish I just had a knob on my remote that I could turn at any moment to move the audio ahead/behind to manually sync stuff up.