i do love watching lightening as you say it makes you think.
on holiday in the usa once we were stood on the rim of the grand canyon and all the way accross the other side 20 or 30 miles away there was the most amazing display of sheet lightening and then individual bolts off down into the canyon. you could hear and feel it as it bounced from wall to wall. absolutely stunning.
where we were stood it was bright sunshine 30 odd degrees blue sky. yet accross the way ive never seen such black clouds.