One of the most exciting moments of the NHL draft is when commissioner Gary Bettman takes to the stage to announce a trade. There's always that moment of uncertainty before he releases the details, then the momentary buzz as everyone takes in the information, and then the explosion of excitement when it's a true blockbuster.
Nothing can fully prepare us for the shock of a draft-day trade, but going back and studying all the recent action can help reveal some patterns that can set realistic expectations. For example, certain teams are far more active on draft day than others. Some teams are known to have a surplus of picks, or have a few extra veterans to move, and there's a pretty clear consensus on the value of each position in the draft.