We have all done something wrong in our lives or have misgivings to others, intentional or accidental, therefore if that statement is true, then there will certainly always be boomerangs coming back at you all the time. Since whether you worry of consequences of your current action or not, there will be numerous source of boomerangs returning, it is futile to be cautious because one of these boomerangs will surely hit you somehow.
Of course, that is assuming that the proposition is true. So far empirically, logically and philosophically I have not found that to be the case.