A former co-worker of mine had a so-called Smartphone.
One night, when he was supposed to relieve me at midnight, he didn't show. Now that sort of nonsense was something I've gotten used to. Well, not really. It was just no longer a HUGE surprise when it happened. Still got my blood pressure up every time it did. Thing is, he wasn't usually the one doing it. He did, early on. But he had gotten much more reliable. Usually when something like this happens, I'm stuck working another shift on less than last minute's notice, until the individual scheduled to come in at 8am arrives.
Turns out, my midnight relief was running late. But he didn't know it because he dropped his Smartphone onto the sidewalk. Touch-screen crapped out. He couldn't call to say he was running late, and he couldn't check the time because the screen was out. He also couldn't pick up if anyone called him, because the screen was out. He honestly didn't realize he was running ridiculously late, instead of somewhat late. He arrived nearly an hour later. I had to go to bat for him in order to make sure the client didn't fire his butt.
That's one example. But I've learned over the years not to place too much faith in cellphones. Smartphones with their touch-screens are ridiculously fragile, even when carried with a protective sleeve. Plus, I'm lazy. I'd rather just turn my wrist a bit instead of digging out my cellphone from my pocket, just to tell the time. And then shoving it back in there.