I've had a Sandisk 8GB class 4 micro SD card since my Galaxy S days. That means I've been using the card for almost 2 years now. It's been in my S3 for two months. It still works perfectly fine. Maybe you bought a faulty one (or even a fake).
The title was hilarious, though. It's like a trailer for a new movie.
Galaxy S3: The Card Destroyer
Tagline: It came from another galaxy on a mission to destroy every type of card known to humanity!
Android devices owned: Samsung Galaxy S GT-I9000, 8GB, Samsung Galaxy S3 GT-I9300, 16GB (Pebble Blue)