Last summer I wrote a spontaneous e-mail to Professor Frans de Waal to share a video of a Borneo orangutan in Barcelona Zoo, showing a very interesting behaviour. He took the time to answer my e-mail with very kind words and attaching an article on the matter. He did not mind who I was; but he took the time to provide some hints to an unknown person who needed to learn. This kind of sensitivity is scarce nowadays. Rest in Peace Professor de Waal; wherever you are now, keep throwing your light to all of us who wish to understand the world.