facetiousness, in all its glory
Here's something that really pisses me off: people who leave their cell phones on "vibrate" all the time. The reason this pisses me off so much is that it's possible the person may have strayed away from his phone and he may not be able to hear the sound of its vibration. This greatly impacts my daily routine because I might end up having to wait for him to call me back, which would suck.
But this pisses me off most not when I'm calling the aforementioned hypothetical phone-vibrate man, but just when I notice someone else calling him. The possible inconvenience caused by using "vibrate" instead of a ringtone certainly overrides whatever possible reasons he could have for using vibrate mode. For instance, maybe he thinks it's easier to keep the phone on vibrate than to switch profiles all the time. Or perhaps he doesn't want to run the risk of being one of those oh-so-annoying people who let their cell phones go off during inopportune times (such as class or church). Or even if he doesn't use a ringtone because he simply finds the common techno or hip-hop beats obnoxious, I still think he'd be better off switching to a ringtone just for those rare occasions that he's separated from his phone.
Clearly, the pros outweigh the cons.