My signature is pretty consistent, my first initial and last name without taking the pen off the page - I spend my life signing legal documents so I had to develop one that was reasonably readable. I've also got so in the habit of including my collar number on the tail of the last letter that I find myself doing it in shops and things. Usually to an odd look that says "that's a weird surname".

Just nod and say, "yes, the 123 are silent"
I'm in the big letter, big letter, scrawl camp of writing. And given that I do it so rarely these days, I need to think to remember what to do!
(I haven't forgotten how to write, I hasten to add, just I don't sign my name very often these days)