We are sometimes dick ourselves, everyone, christian or not. We treat each other pretty much like garbage.
Granted, being christian literally means (among others things) to watch out and be careful with that and rein it in and eventually eliminating it. The virtue of humility is all about that exactly. Virtues are not something you magically have, every virtue is a matter of building habits, good habits.
This requires effort and few people like effort. Even doing the effort required, we may fail from time to time, no one is perfect. That's why we should be forgiving and understaing of other's failings, because we have them too. But we fail in that too! We can't always forgive so easily.
It's hard, you see. Chesterton said something along the lines that original sin (or the fallen nature of man) is the most evident dogma. One just have to look at people (and ourselves) to see the truth of it.
And yes, many atheist or agnostics (I'm not saying that this was your case, nor here or in your town) can come across as smugly, considering us inferiors for believing in fairy tails, or even worse, some have the certainty that we are under some heavy psychological suggestion. And you have no idea how demeaning and patronizing that is. Condescension isn't really the best for building a good communication. Christians are guilty of presumption and sometimes are pushy too.