The reason why cats meow.
1. A cat's "humming" sound may be a way of conveying a message. Observe the cat's physical condition; cats usually make this sound when they are happy, indicating that they are enjoying themselves.
2. When a cat makes a soft "mmm" sound, it's usually because it's in an unfamiliar place or is scared.
3. The cat is bored and wants to play with its owner. 
How to take care of a cat's emotions.
1. Maintain multi-level spaces in your home. Humans primarily move around on the ground; when we're off the ground, we're usually lounging on the sofa watching TV or sleeping in bed. Cats, however, are different. They love complex environments. Besides walking on the ground, they enjoy wandering and resting on different heights—sofas, tables, cabinets, windowsills, even on their owners. Cats also like to claim high places, so owners can arrange furniture of varying heights throughout the home to provide their cats with multi-level activity spaces.
2. Prepare more cat supplies. Our houses may not be very big, but they are actually quite large for small cats. Cat owners can place cat beds, food bowls, water bowls, litter boxes, cat toys, and cat trees in multiple places around the house so that they can use them wherever they go. You can also grow some cat grass so that your cat can chew on it when it's free.
