Cats have strong curiosity and a desire to explore unknown things. When the bedroom door is closed, the cat will scratch at the door out of curiosity to find out. The bedroom smells like the owner, and the cat will feel very safe sleeping on the owner's bed. This sense of security makes cats willing to come into the bedroom, especially when they are cold or need comfort.

Cats are very territorial animals and they will patrol their territory. If the bedroom door is closed, the cat may feel that its territory is being violated and may try to protest by opening the door.

Cats are very dependent on their owners and always want to stay with their owners all the time. If the bedroom smells like the owner, the cat will want to follow the smell all the time. Sometimes when hungry or thirsty, he will go to the bedroom to find his master.