The London ones had a real 'designed by committee' feel to them, in that every aspect of their design _meant_ something - they were grey because they were made from girders from the Olympic Stadium, they were shiny to reflect all the people they met, their bracelets represented inclusion and friendship etc etc etc
Not that these are bad things, but the actual result was so ugly!
I've just looked up the Milan Cortina mascots and they're great! They represent being cute lil stotes, what else could you need?