Can someone give me a BRIEF, SIMPLE explanation of how fees work?  How are they calculated? Why is there a discrepancy in opinion regarding how high the fees will be as we approach more halvings?  Lots of speculation about how expensive fees will need to be in the future.  Any insight, would be appreciated.  FWIW I'm not a computer dude, as much simplicity as possible would be most appreciated.  Thanks in advance!