Can someone explain the 'muse' please?

Most people have heard of 'writers block'. I believe that artists can experience the same thing – a sudden inability to see good subjects, perhaps a lack of flow in a paintings brushwork, the
realisation that your work has dropped below your usual standard.
  
There can be so many reasons of course. A loss of the 'muse', some sort of altered mental state, my first time out of New Zealand and being away from everything familiar, the general upheaval of travel, even jet lag could be a handy excuse!
  
(I'm not really sure what the 'muse' is when I think about it!)
  
Of all the times to pick on, I experienced this artist's block while Richard Robinson, a painter friend and I were in the USA just recently to go to a Plein Air Convention and to do some painting with other friends in California. 
 
First - the convention - a great time of learning, meeting people,(about 800 of them) and seeing top line painters demonstrate. 

We plein air painters prefer nice calm conditions but the weather was not always kind to us – quite cold and windy for a time when we first arrived. However,on the last day, we went to paint around the cafes and boat moorings of Monterey. At last the wind dropped and we had sunny, mild conditions. A great group to paint with too as most of the people at the convention gathered in one place. Mind you, I struggled with this painting of the boat harbour at the bottom of this blog for some time, but at last, I was happy with the outcome.

With the convention over, we went up to Yosemite national park. What a fantastic place!
 
I felt particularly inspired by the beautiful colour of the water and the pearly white granite rocks around the river flowing out of Yosemite. I felt the urge to paint big. (This is a common experience for me.) BIG mistake!! I struggled with the painting all day and although I've put it at the head of this blog, I feel that it still needs finishing. I like it so far though!

It's frustrating when things go this way. It's so much better to travel home with a painting that you are pleased with and that you feel is finished. However, despite not painting well, I don't want to sound as if it was all doom and gloom. We had a great time. We saw and stayed in great places, I had good company, they even helped with my painting gear at one stage when I was struggling, and I found that Americans are so very helpful and friendly. (They can't make really good coffee though!)

Will I go to the convention again next year?  I'll have to work on it as two 13 1/2 hour flights in a cramped seat feels a bit daunting just yet!