Every year teams take chances on players in the NFL Draft, there is no doubt about that. On the other hand, sometimes sure-fire picks fall down the ladder further than expected and right into a team’s lap. The difference between the two is pretty simple: the former is considered a reach while the latter is considered a value or a steal.
Now, depending on which side of the semantical/subjective fence that you are on, depending on the player, it could easily become a reverse scenario than what I just described. Regardless, either situation is guaranteed to crop every year.