I've been resisting going out to paint for awhile, even though the weather's been just fine. I think it has to do with "mission creep."
Last year, I'd come up with a few paintings that were good enough to frame, and it influenced my expectations. You start with a healthy, reasonable goal of having fun, learning a bit or making a souvenir sketch, and then you start to think maybe you'll do something brand new that's never been done before or make a beautiful painting, or make something that will sell, and there you go, skidding right off the edge of reality.
Being hopeful is a good thing, but sometimes if you aim for less, you actually accomplish more.
Last week I finally went outside to paint. I had some watercolor paper that had a purple wash on 2/3rds of it, and I knew that this painting would be strictly for fun. I could scrub away parts of it, but on the whole it would be an experiment in purple & green. No pressure, no apprehension.
A limiting factor can actually be a source of inspiration. Chose one... small size, simple subject, limited palette, a textured surface or an unusual background color, a complete lack of detail, very limited light, a series of the same view, doing only trees, or only roads...
Of course, as long as you're THINKING about painting, (shapes, movement, negative space, patterns, colors and the way they interact with each other and with light & shadow, mood...) you're still on your mission.