Unfortunately that doesn't happen much, pet stores especially thrive on impulse purchases. I've worked in a pet store, my mentality wassn't appreaciated.
If you talked to my co-worker, you left with an animal and a 120€ bill, if you talked to me, you'd lose a half hour at minimum and left with a bill twice that if you din'd change your mind by the end of the conversation.
People don't realise pet stores don't inform them enough and often, they feed them absolutely wrong information.