Namely flags.  They should be seen on and in government and embassy buildings; on ships so their Nationality can be identified; ditto for the military; and a few other select locations where it is essential or helpful to note the nationality of the Flag bearer.  Barring waking up with a complete loss of memory on someone's lawn and using the flag there to identify your approximate location on the globe (assuming you only have short-term memory loss) the whole idea of flying a flag on your porch seems ridiculous to me.  Even though I abhor expressions of collegiate pride almost as much, those make slightly more sense to me:  you actually decided where to go to college (even though chances are you got rejected from your first choice). 

But you cannot choose where you were born.  If you like your Country, great, but understand that it it was a completely random event and that you were lucky to have been born here and not in some misery-riddled backwater of a nation.  No need to shove your relative affluence in everyone else's faces.  Also understand that you are not in the 'greatest' country in the world, or 'the best' or '#1'.  As you are only a citizen of your country (maybe of two) you do not have a basis for comparison because your data set is extremely limited. 

And please, flags are not clothing.