Getting over someone is a grieving process. You mourn the loss of the relationship and that's only expedited by 'Out of sight out of mind.' But when you walk outside and see them on a billboard or on TV or on the cover of a magazine it reopens the wound. It's a high-class problem but it's real.
A pet store is a celebration of dogs' existence and an explosion of options. About cats a pet store seems to say 'Here we couldn't think of anything else.' Cats are the Hanukkah of the animal world in this way. They are feted quietly and happily by a minority but there's only so much hoopla applicable to them.