I used to have multiple levels of "to do" lists. Sometimes in writing, sometimes just in my mind. (Yeah, I'm a little over-organized at times.), The lists were something like "do ASAP," "do this week," "do this month," and "do this lifetime." A lot of those have dropped off the list, like "go back to taking piano lessons for the first time since 3rd grade." Just not going to happen, and don't care anymore. No just that I have much higher priorities, just don't care. Some things have dropped off because I do have higher priorities, like learning multiple languages. It would be cool, it would have very some minor practicality, but just not worth the immense amount of time it would require.
I'm a bit down about some things that I would really have liked to achieve, but didn't, and simply isn't going to happen now. Some of those things I actually wouldn't want on a practical level, even if they were handed to me on a silver platter, but ego often overrides common sense. Example, I wouldn't actually want to be Derm Division Chief at McGill. It's really a lot of paperwork, meetings, and bureaucracy for minimal prestige, very little real authority, and no money. And for what? Another line on my CV or maybe my obituary? (This is ignoring the fact that I tend to tick people off and they wouldn't offer it to me anyhow. Not sour grapes, realistic appraisal.) A bigger one is that I didn't make general in the Army. I was a Colonel and a Brigade Commander, which is way further than most people get, but you always want that one more/one last step. What triggered those thoughts was looking something up about the current structure of military medicine, and seeing that 2 people I knew had moved far up in the military and civilian hierarchy. One I used to work for, and I respected. One had worked for me, and although competent in some ways, was rather a jerk. (Come to think of it, someone else I recall who had worked for me also made Brigadier General, but she was really, really good.) There are some other minor things, but these are the two glaring ones right now.
I think it's an age thing. (Getting old? Who me?) At one point I would have liked those things. Even after I'd missed my realistic shot at them, I still used to fantasize about them, but can't even do that any more. Bah.