This is a real pain, as households will often be using just one Goggle account for maybe one person's phone, the shared computer and smart TV, and they're all interlinked. My biggest gripe is that Netflix thinks I'm a combination of my wife and daughter, and keeps recommending reality cooking shows and historical dramas I have zero interest in.

You pay for and/or go through the inconvenience of setting up a different account for each device/family member, or all the data gets mixed up in one big cauldron.