For mechanical things, I think your father is exactly right. For programming and text editing, I think it is different. If you don't have the right sized socket wrench, probably all you are going to do is destroy whatever you are working on. With programming, i.e. editing text, it's a different story.

At the extreme case, I'd trust a vim or emacs or eclipse user with my next big project far more than I'd trust a user who willingly uses notepad.