The fairies continuously made everything worse
1. Completely sheltering Aurora. Merryweather's gift was Aurora falling asleep until her true love kissed her. She gave this gift before the fairies planned to hide Aurora in the cottage. But they still decided to keep her completely away from anyone else. With a true loves kiss being required, wasn't that just stupid? How can her true love kiss her and save her if she doesn't ever meet anyone? If she hadnt accidentally met Phillip in the woods, she'd have been asleep forever.
2. Being so careless with the magic. Obvious one. Got the attention of the bird, and gave Maleficent her opportunity.
3. Not waiting to bring Aurora home until AFTER her 16th birthday. Wait until the next day for gods sake! She'd have been fine!
3. Making every other person sleep until Aurora woke up. This was just short sighted. Couldn't they have used some help? Once Phillip got taken, it was literally only down to the three of them to save him, and every other person from sleeping forever. Probably could have used two kingdoms combined armies to attack Maleficent. Even as a distraction or something.