If you were to see the Hogwarts Sorting Hat out of context - say, hanging on a peg in a pub - you'd probably think, "Well, that's a ratty-looking hat, isn't it? Why doesn't that person just chuck the old thing?" But as you know, this hat holds much power. Not of determining life and death, of course, but close - the power to put a Hogwarts student in the house they'll thrive or fail in. That's pretty big, especially for a lowly hat.
Not that the Sorting Hat is infallible. One could argue that the esteemed headgear sometimes got it wrong. For example, Hermione Granger. One of her main characteristics was ambition, which made her the cleverest of her year's witches. But Hermione could never think "outside the box." Her bravery, a Gryffindor trait, had strong Slytherin tendencies. She had to think before taking action - but having decided, was never afraid to break the rules - a clearly Slytherin trait.
So, even magically enchanted hats make mistakes. But we're sure that won't stop you trying your luck being sorted into one of Hogwarts' hallowed houses. This section has hundreds tests on the Sorting Hat! Most are of the "Which house are you in?" variety, but there are a few that go deeper or tackle a different aspect. Try all of them if you want - we won't stop you!