For starters, the old-fashioned landline phones offered a foolproof excuse for so many unpleasant things: "Sorry, I'd love to attend your (PICK ONE: baby shower/retirement party/pot luck picnic) but I have to be at home then as I am expecting an important call from my (PICK ONE: doctor/lawyer/child away at summer camp), so I'll have to pass.
Another thing I miss is the fairly commonplace adventure of getting lost on your way to somewhere you've never been. Now it's impossible, what with that damn invisible lady saying, "In 40 yards turn left. In 20 yards turn left. Turn left." There's no more spontaneity! Gone are the days when you might stumble upon a great little diner where the guy behind the counter draws you a map to where you're going on the back of the menu, and they have great pie too.
Obviously, conversation with strangers is a thing of the past. I certainly am guilty of this, pulling out my phone whenever I'm stuck alone somewhere, like in a doctor's waiting room or at the airport or in a restaurant, instead of talking to someone sitting nearby.
The very worst thing about cell phones is that there are no more arguments about anything. Someone, usually my husband, or my son if he's there too, always whips out their phone and Googles the answer and that's that.