My cat follows me around everywhere

I’ve been living with my cat for 4 years. He loves to sleep and has always been a pretty lazy cat, but all of a sudden he is following me everywhere I go. It doesn’t matter what I’m doing, whether I’m going to the kitchen to make food, the bathroom to piss, or even to the shower (he’ll sit at the shower curtain the whole time). It got me thinking... why is it that animals can be very unpredictable? The only time my cat was predictable was when he was hungry. This behavior is very new and a drastic change from how he acted before. I personally think that animals must be very unpredictable to make us think that they have their own personalities, but maybe they’re just glitching and they don’t know what else to do.