Maybe part of this problem is can be attributed to a language barrier - it might have been better to say, "hey craig, maybe you made a mistake...what about this data?" rather than, "you're a liar!"
Calling someone a liar is much more inflammatory and insulting than just insinuating that they've screwed up on a detail or missed something....No matter who is right or wrong in the situation.
Now, I can't wait to finish work and get home to play with my HO!