So rude…getting a wrong number, and just putting the ‘phone down

This is a mini-rant. If you ring me, and accidentally key in the wrong number, and realise this when you hear my dulcet tones answer: please, just say “Sorry, wrong number” or some-such, before you put the ‘phone down. It won’t hurt you, I promise. I just don’t understand why it’s so difficult, given that we all do it.