If you say you're going to come and pick me up in 10 minutes, make sure you come and pick me up in 10 minutes.
I didn't get the memo explaining any changes, so that just makes you a liar. You also carry a phone everywhere with you, which incidentally is permanently attached to your ear, so why can you not ring me and tell me you're running late which allows me to do other things while I wait instead of just waiting for you.