What could possibly go wrong?

Yesterday, we made a pretty good list of factors that interrupt effective communication. Here is the list we came up with as a group:

pre-judgment (deciding too early - on the message, on the intent, on the course of action, what you're going to say, etc.)
being closed off/defensive/disengaged in general
language barriers (including differing accents/dialects)
cultural barriers
non-verbals such as facial expressions, tone of voice, body language
speaker is unclear what he/she means to express (not explaining clearly, muddled thinking)
humor or using sarcasm
distractions including own emotions, technology, looming deadlines, higher priorities
speed at which someone speaks or rambles
speaker & audience have mismatched skill-level/comprehension level
competing interests - want two opposing things so send mixed signals
making assumptions (that don't match true intention or need)
gender differences
generational differences
differing expectations from communication (expect resolution now, want to delay decision)
speaker or receiver's mood
trust level
history of conflict in the relationship
different values (M.O.) - including disinterest in the subject in one or the other parties
MATURITY

With so many barriers, it is a wonder that we understand each other at all! What could possibly go wrong.