Gossip Girl / painters block

I think I should be painting more cows.  In general.  I mean I love their shape, their colors, their personalities.   It is one of the subjects I come back to often and when I'm in a bit of a rut, it is one of the only subjects that is almost guaranteed to remind me of how much I love to paint.  I sometimes get intimidated before I even put paint on my palette.  Yeah,  it's fear of the frustration that I might be setting myself up for.  That frustration can be really emotionally draining when the passion to create is so strong.   It usually doesn't happen when I paint the cows and trees though.  I don't know why I feel the need to share my thoughts on this except that I believe some of you other artists must also struggle with the same hesitance to get started on a painting.  Of course at this stage of my career I know to ignore those feelings and to fight through it which almost always works itself out just fine, but it is very interesting to me that I still have bouts of utter (no pun intended :) insecurity. Just keeping it real for you guys.  Let me know if you can relate, I'd love to explore this phenomenon... painters block I guess.