What drives a painting to completion? Much I'd say is the composition, particularly with abstracts, opposing shapes, color and rhythm to complete the painting in a satisfactory way to the eye. Striving to keep visual intrigue and interest to stand above the common denominators.
The reason I love to work on a large canvas is that there is plenty of space and movement in which to work out a love story/composition in paint. The smaller I work the tighter the composition, even though that wasn't the intention. When exhibiting a large painting one needs a free space in width and height to allow the painting to breathe and exist in it's rapturous entirety.
The abstracts I produce are spontaneously composed and developed, even rather accidental in nature. I like as much of a discovery while creating as someone seeing a painting for the first time. The degree of articulation and observation can be intense and tiring after a long day at the studio. Artists use their keen aesthetic senses to be architects of their own creations, balancing, pushing and pulling, making minute adjustments no one else would analyze and take into account in a completed work. At some point we turn and walk away when our highest artistic abilities have endeavoured to produce a painting worthy of being hung in the hopes that someone else finds intrigue and interest in what we labor over. We paint to bring joy to others!