All communication between people involves filters.  Just because we tell somebody else something doesn't mean they received the same message we intended to send, or that their response will be what we anticipated.  Our response is always based upon the relationship we have with the person sending the message and it is based upon our belief of what their motive was.  We filter messages through the "why did they say that" filter.  When we say thank you we can get responses varying to genuine appreciation to anger and suspicion based upon the relationship we have previously built with that person.  Leaders must understand this dynamic.