Helmut Heller, Physicist, Leibniz Supercomputing Centre, Germany
My PhD supervisor, Klaus Schulten, showed me Mathematica on his Macintosh computer back in 1989 and it was unbelievable! I had had no idea that something like this existed. A real WOW moment!
I then used Mathematica myself in my PhD work on the NeXT computers in Schulten’s lab at UIUC. I am still using Mathematica every now and then nowadays, although I am now managing a group of 10 people and doing less “real” work myself.