It's very common. I travelled an awful lot on business. On one trip from NYC to Chicago, I went to check in at La Guardia. The AA staff were puzzled, as the flight was from JFK! The e ticket and confirmation both said JFK, but I had assumed that as it was a domestic flight, it was from LGA! Hence blindness when looking at the ticket! I now check obsessively. Luckily I also leave a lot of time.e when checking in, so made it to JFK. Felt an absolute fool. Years before, I was in SF, going to Santa Barbara. I rang up the hotel to check the reservation, and like the member above, had the wrong month! This was expensive, as they only had a suite!
The other issue, I find, is booking hotels many months ahead, especially if you have a duplicate booking, as you can do with booking.com. Unless you are very careful, you can forget one of the bookings. That has happened to me!