Some strange habits can also be related to their diet. If your cat isn't getting the right nutrients, it might behave oddly. Also, changes in the environment can make a cat develop new habits. For instance, a new pet in the house or a rearrangement of furniture.
Cats are very sensitive to their surroundings. A strange habit could be its way of coping with stress. Loud noises outside, or a change in your daily routine can stress a cat out. It might start doing something strange like hiding in unusual places to feel safe.
Well, it could be due to various reasons. Maybe it's part of their natural instincts. For example, if it likes to scratch furniture, it might be marking its territory. Or perhaps it's bored and needs more toys or interaction.