Making great progress with my painting

So I stayed up until about three thirty this morning painting. I'm getting ready to
transfer my charcoal images onto my canvass. I think this painting is going in the
right direction.
It baffles me how I can start a painting and it's going great and then after I've finished it, I don't like it. Or I might love it and then days later I hate it.
Why is that a part of the process? I haven't had one painting that I loved the whole
time after I've finished it.
That elusive masterpiece is always eluding me..............

One day I'll love one and will continue the entire time.
Until then......
Adrienne