Taboo

We had one week that brought up the question of what is considered taboo. We had a sign up with the following:

Taboo:
When the belief exists that saying a certain word or speaking of a certain topic is unacceptable, either
1) because it might evoke that thing,
2) it might be considered too sacred, or
3) perhaps it is too profane

What topics are taboo at church?
What things do we never talk about at church?
Why?
Should we have taboo subjects at church?