Ever since I binge-watched 'The Walking Dead', this question has gnawed at my brain like a zombie on fresh meat. The way I see it, zombies aren't making a conscious choice - it's pure instinct, like how moths fly toward light. Their rotting brains probably register humans as the most accessible source of 'life energy' or something equally primal.
What fascinates me more is how different media portray this. In 'World War Z', the zombies swarm like ants toward noise and movement, while in 'Shaun of the Dead', they're almost sluggish in their pursuit. Maybe it's not about preference at all, but rather that humans are just the most noticeable prey in most apocalypse scenarios. The real mystery is why they never seem to go after animals with the same enthusiasm.