h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Telephones keep being given more and more features. Last number redial, number storage, call forwarding, call forwarding to different numbers depending on the caller's number, different answerphone messages depending on the day of the week and so on... These are all very impressive, and would be great, but the telephone hides them from the user and makes them scary to use. Take my phone as an example. It has the following buttons: numbers 0 to 9, '*', '#' and six unlabelled white buttons. It has a vast number of special and powerful capabilities, but I don't use any of them. According to the great big thick manual I saw once, redialling the last number I rang is a simple matter of pressing '#4'. Or is that '#7'? Or maybe '*5#'? I am scared of using these hidden features for fear of pressing the wrong buttons and accidentally redirecting all incoming calls to some complete stranger's internet-enabled toaster. I assume the mysterious white buttons are programmable with frequently used numbers, but that's too frightening to even contemplate. And yes, I know I ought to read the effing manual, but honestly can't be bothered. Nor can I find the manual.