Only Ever One

Wht is it that when you come across something like this which should be in pairs, there's only ever one? Seen in the car park on my way to the aunt's funeral earlier today.
If it's a glove, it's only ever one. Same with shoes and anything else which should have a partner. Whatever happens to the other half? Do people have wardrobes full of single items, having lost the other one? Whatever happened to the other croc of this pair? A great mystery.