i think it is nice when we are inspired to meditate and it does not become 'mechanical' that is why it is wonderful when we wake up in the middle of the nite and can't go immediately go back to sleep to meditate. We should entertain the idea that we are often given inspiration from higher sources to practice our spiritual routine and not ignore it. i like no lite or very dim lite when i meditate. But i suppose other people may feel differently. Too much lite makes me too aware of the outer world and takes attention away from the inner world.
Sometimes the energy of a full moon has this affect on us also.