Heh sometimes I am still doing that. modern bidirectional raytracers can do some interesting tricks. and I wanted to see caustics(the bright lines in pools). but caustics despite being bright are actually statistically rare. to get good caustics you have to unbound the render engine and just let it cook overnight.

And the end result, a single image of a mediocre scene by a poor artist with amazing caustics. I won't be quitting my day job.