That's the wierdest question
I usually have my shoes off, if I plan on going for a run or going to the store I'll usually throw them on. I don't see a problem with wearing shoes inside unless you just stepped in fresh dog shit.
As for it being a politeness thing I can understand but I feel wierd going into someones house I don't really know and taking my shoes off. Sometimes I'll ask and if they say to take them off I'll say FUCK YOU