It's not that hard to do:
You say you'll be somewhere so just show up. If you can't make it then call. I don't understand how people can continue to be inconsiderate of others and their obligations. I may set aside any amount of time to have an interaction with someone and if they do not render me the same courtesy, everything is ruined.
Sure you could have had an emergency that would have prevented you from attending our "date", but can't you find some way to let me know? Tell the ambulance driver my name and number; better yet, if you are traveling in an unsafe way like walking, riding a bike, driving a car or flying then just pin a note to our chest that says where you are going and who you are going to meet.
Ok I just invented something amazing. It will be a little pouch that you wear around your waste that can hold your wallet, keys, phone and a little note that reads "on my way to see darren, please let him know I had to cancel if you find me dead". I'll call it "The pouch full of stuff you should have remembered but didn't care enough to take care of before you left your house"...or "Fanny Pack". What do you think?
