I'm certainly not as ambitious as I was when I was a lot younger. That may be true of most of us.
My first job after leaving the university lab where I was working after graduation was as a GS5 engineer at Indian Head. I'm a self-loader and took on all assignments with a lot of energy. Soon, I was getting many of the more interesting/challenging assignments in our branch. Got the calendar-controlled steps to 7 and then 9. Then I was selected to take over a GS13 Senior Engineer position at Radford. I'd been working there a lot and the guy in that seat had been in it for 45 years (since the plant first opened to make explosives for WWII !) and selected me to be his "successor". Took a lot of effort at higher levels to get the approvals required from a GS9-GS13 jump, especially since I had
just gotten the promotion to a 9.
Then I woke up and looked arond. I realized that I was doing a lot of the branch productive work..and everyone else got the same clockwork promotions I did. I realized that the GS13 position I'd been "honored" to be selected for was truly a dead end...there was nothing above it. Ever.
Then some of my propellant production line people were killed in a preventable accident.
I bailed.
There have been some times where, as a business owner, I wished for the guranteed income of that CS world..but then business would tick up and I'd slap myself for thinking that way.