In general domestic cats follow their owner for the same reason they follow each other: friendship. People ask why their cat follows them to the bathroom, toilet or when they go outside. This is one of those instances when the underlying reason is a common sense one: they want to be with you as a “preferred associate” or what we would call a friend. In particularly close relationships cats can be imprinted on their owner regarding them as their mother which is why they follow. I think true imprinting, as it is described, is quite unusual. Normally when either cats follow each other or a cat follows their human companion it is because they like the company. Obvious, yes.
Nowadays my cat is an indoor/outdoor cat. When he goes outside he wants me to join him whenever it is – day or night. He wants me to explore the outside with him. Perhaps it makes him feel more secure and of course he likes the company. He finds it difficult to understand why I don’t want to hunt all night. Perhaps he is pissed off with me for my lack of interest. This goes against the grain of the concept that domestic cats are entirely solitary animals. They are not because 10,000 years of evolution of living with humans has turned them into quite sociable creatures. There’s no question that my cat likes to be with me and he is able to do so more or less whenever he chooses because I’m retired from the usual 9-5 work and therefore around a lot.
There’s an additional reason why cats follow people to the bathroom. The bathroom is a place where their human companion presents herself to their cat in high definition. This is because they’re either wet after a shower or they’ve had a poop or pee. All three activities results in the release of body scents which renders the person in high definition to a cat. This is because they use their sense of smell so effectively and so importantly. A cat’s sense of smell is as important as their eyesight. Scent to a cat is an identifier. Domestic cats often become excited when with their owner in the bathroom for these reasons.
The obvious added reason why cats follow their owner to the kitchen is because they are asking for food. It’ll be part of a well grooved routine. There may be other behaviors such as the meow-demand or other sounds.
Outside cats following strangers
Sometimes when I’m walking outside, on the sidewalk (pavement), I might bump into a cat and that cat might follow me for a while. This cat is looking for company. It is likely that their owner is away all day at work. They’ve gone outside and they’re confident enough to approach a stranger and even to follow them for a while such is their desire for human interaction. However, it is more usual for outisde domestic cats to move away from strangers because they are inherently unsure if they are friendly or hostile.
The answer to the question in the title is readily seen in photographs and videos of cats living in colonies. You will see friendships or what the experts call “preferred associates”. Experts don’t really like to think that cats make friends with other cats. They prefer to label it more scientifically. But you will see these cats walking around together, rubbing their flanks against each other, sometimes intertwining their tails and head-butting each other (scent exchange). Clearly they are friends and as a consequence they follow each other around. It’s the same in the human to cat relationship.