My parents used to have a Grandfather clock that you could hear ticking from my room on quiet nights and it chimed every hour. I always missed the noise when I slept away from home.
For puppies we used to always put an alarm clock in their basket for their first few nights because the ticking helps them settle. They advise the same for kittens. The ticking helps to simulate the regular sound of a heartbeat.
I guess that it's one of those things that would drive you crazy if you weren't used to it but can be a comfort if it is familiar.
I hate seeing a clock when I put the boys to sleep because I end up clock watching and it does my head in.