In this article I'm going to discuss a problem few people think of. Computer simulation of various processes becomes more and more widespread. This technology is wonderful because it allows us to save time and materials which would be otherwise spent on senseless chemical, biological, physical and other kinds of experiments. A computer simulation model of a wing section flow may help significantly reduce the number of prototypes to be tested in a real wind tunnel. Numerical experiments are given more and more trust nowadays. However, dazzled by the triumph of computer simulation, nobody notices the problem of software complexity growth behind it. People treat computer and computer programs just as a means to obtain necessary results. I'm worried that very few know and care about the fact that software size growth leads to a non-linear growth of the number of software bugs. It's dangerous to exploit a computer treating it just as a big calculator. So, that's what I think - I need to share this idea with other people.