People often fail to keep their promises because they don't manage their time well. They might take on too many tasks at once and then realize they can't do everything. Sometimes, they think a task will take less time than it actually does. Unexpected events can also throw off their plans, making it hard to keep promises. Balancing schoolwork and personal commitments can be tricky, leading to broken promises.

Sometimes, people fail to keep promises because they lose interest or motivation. They might have made a promise because they felt they had to, not because they wanted to. Over time, their priorities or interests might change, and the promise no longer seems important. Peer pressure can also lead to promises that aren't genuine, making it hard to follow through.

External circumstances can also cause people to break promises. Things like illness or family issues can make it impossible to keep a commitment. Sometimes, people rely on others to help them fulfill a promise, and if those people don't come through, the promise is broken. Financial problems or unexpected weather conditions can also interfere with plans, making it hard to keep promises.