Maybe you have heard the story of Ted Bundy, how he confessed that he once was going to harm a girl but stopped at the last minute. She had fallen asleep with a rosary in her hand. He saw the rosary and felt convicted not to go forward with his actions. He left her there and then was caught just a few weeks later. How much impact can a sacramental have on our lives? That is just one story to show that it can do far more than we ever realize and there are many more.
How does this relate to the specific actions that we perform in the Mass? Not just the bringing of sacramentals, but the other deeds that we are required to perform? How much does the manner that we cross ourselves impact our spirit? If we are lazy in it compared to if we are diligent does it make a difference? How about if we choose not to genuflect when we really could have done so? Or if we only mumble a response rather than speaking it clearly, does it really have an effect?
The theology of worship would tell us, yes, all these things make a difference. The way in which we perform any duty is both outward and inward. We can inwardly love God, but not show it outwardly (which, if intentional, means that our love for Him is about to die). We can genuflect outwardly, but actually be rebelling inwardly. It has been said that whenever someone leaves the Church, he has always already left in his spirit long before he leaves in bodily fashion.
Do you wear a crucifix just because you are used to it, or because you know it has a spiritual impact on you? Do you pray before meals because that is what we do as Catholics, or are you really thankful for every bite of food that God provides? We do not always consider the rippling effect of each and every action, but we should. Sometimes these things might be the very action that saves our lives (both spiritual and physical).