Well, a thesis statement is a short statement, normally one sentence at most, that summarizes the claim or point of your essay, research, etc. And it's developed throughout the writing, with supporting details and such. Normally, I like to word my thesis statements in introductory paragraphs, because that works best, and that's what it is, an introduction. So you could add a little umph to it. For example: "How we behave in public acts as a sort of social glue." And add on from there. Or: "How we act around people, and in general, acts as a magnet, better manners attract people, while bad manners push people away." And add on from there. Also maybe think of some more vivid words to help you. For example, social glue is very eye catching, but it might not be the best word choice. Maybe instead of glue use magnet.