Are cake orders like London buses?

Why does it seem like orders for cakes are like waiting for London buses? For months on end, I don't get asked to do any but in the last month or so, I've made two (and fitted in a holiday to Lake Garda!). The first was a fairy castle cake for Macey...



... and the other a 70th birthday cake for a family friend.


Now what number bus am I waiting for now...?