Unfortunately, it's very hard to understand how training attention in this manner can provoke dramatic improvements in attitude, happiness, and even conventional life goals. This is where a lot of the work in modern Buddhism is being done, and I personally believe we need to integrate these techniques into our everyday systems and ways of living. Otherwise, it's perfectly reasonable to dismiss them since good, objective evidence of their efficacy is hard to come by.
Perhaps a useful framing for readers on here is in reprogramming your self. We often accept that we cannot change or even that we want to change. By training our attention, we can focus it on the way the mind itself functions, and this eventually gives us the power to rewrite or rework core parts of our selves. The body contains the source code to our perception of reality, and when we can truly let go we find that we are free to be the person we want, and it is in fact our destiny.