Never cut a cat's whiskers.
Cats' whiskers are actually sense receptors and if you clip or damage them, cats will become disoriented and confused (much like you if you were blind-folded). At the base of every whisker is a special sensory organ, a proprioceptor. This organ is part of their nervous system and helps them detect their location, changes in air currents, and is part of the reason felines are so graceful.
You can also get clues to your cat's mood by the positioning of its whiskers. Tilted forward means the cat is curious. Tilted back means it feels threatened. A normal sideways posture means your cat is relaxed.
Cats are far-sighted so, they generally locate their up-close favorite toy by sensing its location using whiskers. They can also determine the approximate width of a space to know if they will fit or be trapped or not (sometimes, hilariously, this does not apply when a cat decides it wants to sit in a box or a vase or something way too small).
Whiskers are important to your cat. Please don't treat them like ordinary hairs and never, ever, cut a cat's whiskers!