Great question - I think about this a lot now. I had stages of happiness, but at the time I didn't understand it.
Undergrad was a slog (mechanical engineering with ROTC scholarship at a state school, i.e., I taught myself) - I was exhausted at the end of it. I didn't realize it at the time, but I was a fairly attractive young lady. Like W2R, I didn't pay much attention to that as I was focused on my intellectual pursuits. Then my first Air Force assignment was challenging as well. I quit and went to graduate school - loved it. I loved the subjects, I played badminton, I had a lot of fun. But I purposely changed my mindset due to what happened during my first AF assignment. I realized I did not have balance in my life and that a lot of the stress I felt was self-imposed with regard to my standards for performance. That became very evident many years later when I had to review my performance assessments from that time; I believed I was ineffective and poor at my job; my supervisors were tracking me for below-the-zone promotion. Talk about cognitive dissonance.....
My best time was mid-30's to mid-40's (so far
); I was single again, in great shape, loving my job, having fun with skiing, badminton, socializing, learning....in the middle of that I came to live in Europe the first time. It was supposed to be for 6 months; it became 4 years. I was fulfilling a lifetime dream of mine to live overseas and travel. It was *great*.
Fast forward to now; I am happy because I choose to be. I have had some very challenging years in the interim, however, I have built a lot of resilience and know myself much better. This year has been challenging as many of the pursuits I use to 'decompress' have been off-limits. I have lasted longer than most around me with regard to my fairly even temperament and/or positive approach, nevertheless, it has not been easy for me. I tend to over-analyze and want to control what I believe I can control. As I age, that locus of control has diminished through knowledge ;-), so the concentration has deepened on that which I can control.
Barring any serious health issues, I see good times ahead. Even with health issues, the challenge will be to maintain a positive outlook and realize I still have a lot to be thankful for.