We as a species spend an awful lot of time in the past and the future which a lot of people do discuss in various areas of life, such as most third wave therapies and personal development courses you would go on today. Or since the advent of COVID you would attend online rather than actucally be there in person.
Humans therefore also spend a large amount of time thinking about things they spend less time actually actively doing. This may be your specific hobbie where you are so enthralled by your hobbie that work is just something you do to give you the opportunity to work? However for a large portion of the working population the amount of time spent thinking about the interactions that have happened at work or the interactions that they can predict may be on the horizon at work is a huge drain on the time we actually spend alive.
If you work out that we have 168 hours in a week and that an average job might officially drain 40 of those hours you have 128 hours left over. Sleep 8 hours a night and that removes another 56 hours putting you down to 72 hours. If it was all as simple as that we would have 3 full days spare??
Well of course it is not that simple and every day there is time for eating, bathing, shopping, commuting, housework, exercise and chores - this is not an exhasutive list I am sure you can agree.
The point here is in those other 72 hours how much time is spent thinking about the 40 that pays for our life in the other 72? I would suspect if you are like me that this is annoyingly higher than you would like to first admit or accept.
When I was in my teens it was windsurfing I was constantly thinking about when I was not doing it. I did not spend much time being worried by studying as it all seemed to work out.
Then when I was in the working world I craved for the ability to be part of a project and drive it forward. I spent every waking moment when not training thinking about how I could streamline the admin system. I had a boss once who admitted when he asked a techy team, within a customer's company, how long it would take to deliver the online system he was discussing they said 18 months. I had developed ours that far in 3 months. TBH I had not slept much. But I had a completed a working system.
This is true for hobbies as well. I have recently, as a consequence of lockdown, taken up cycling and when I was going out as many days as I could in a week I was also thinking about routes, maintenance and a lot of time online shopping as the winter grew near, getting appropriate lights, clothing and equipment.
The point here is we spend a lot more time thinking about the area of our lives we spend less time actually doing. Being in the here and now rather than worrying or ruminating can have significant postive impacts on your mental health and wellbeing. Try it, notice when your mind has taken you back to work when you are actually walking in the countryside or doing the dishes.