Avoiding social awkwardness seems to be “the easy way” of which we have been warned not to pursue. We are also properly admonished to make no oaths, none at all. I know that most would consider such a formality to be harmless, but God takes it very seriously, nevertheless.
I do not think there is anything wrong with being polite as long as Truth is not sacrificed for politeness.
And as I do believe, this article and/or what I posted above clearly shows how, even if one does not wish to be Catholic, you aren’t going to offend God if you call a priest “father”.