Time is weird and most people think about it all wrong. Like you said with your dogs, once you have a deadline, it feels much worse knowing that in the next XYZ, it could be your last time together.
We only think about time when we are running out of it. Like being in college and worrying about finding a job in senior year versus spending the whole 4 years from the outset planning and executing on getting a high paying job.
“You act like mortals in all that you fear, and immortals in all that you desire.” – Seneca