I'm probably the same as you and I rarely feel I've totally executed well. A ton of bike races (lots of TTs; they are popular here), tris and open runs. Of all of these I'd say I am most happy with my runs performances, which is ironic because I am a strong cyclist/swimmer and running is still progressing. I've swam so much throughout my life that I've never really cared one way or another on my swims. I am always critical of bike performance with a few rare exceptions where I've just throttled it. Running has been a later to me in life sport and is interesting. I have my marathon time to a fast clip (for me) and any time I run I am pleasantly surprised, mostly due to not having high expectations.

However as someone now sidelined with illness for a prolonged period, I can't help but to look at my performances longingly wondering how hard it is going to be to regain all of that fitness. I should appreciate all of this more. Lesson to future self: enjoy the process and appreciate good health no matter what the end result is.