Some paintings work and some don't. If there's no hesitation and no scrubbing off and re-doing, that's generally a good sign. On the other hand, there are paintings which refuse to co-operate, no matter what the artist tries. This can be a dark and lonely experience, especially if your identity and sense of self worth is tied up in what you do. I think a lot of us have trouble with the depression which accompanies failure. It can get pretty bad. My heart goes out to you all, and I'd like to hear from anyone on how they cope when things go wrong. The more ideas we can share the better!
With 'Airport', though, I was lucky. I really love this painting - with everything I tried, it just said "Yes"! It'd be a really different world if you could just bottle that magic mood...