When we forgive our offenders, does it mean we do not want God to punish them anymore? On of the biggest issues i have had with easily forgiving is because of some (ill advised?) thought that  doing so automatically exempts the person from punishment, i know its naive,  but when one is young, that would be the best one could do. But  i think that this may not be the case. I read in a christian leaders webpage (iv since lost the link to the page) that refusing to forgive because of some form of fear that the other party will sort of get away with it  'reveals a flawed eschatology' he argued since  even Christ when just about to be crucified asked Peter to put back his sword, since if  he saw fit,  Christ would have asked for angels. From this he argued that we do not necessarily have to think the  person will not be  punished to forgive, rather we are letting God  deal with punishing them. (Im talking about dealing with unforgiveness of major events, stuff that we may struggle with over long periods).

What does it mean (or involve) to forgive? 

1. Let them of the hook so they do not get punished.
2. Let them off the hook so God is the one to punish them.
I'd say that we forgive each other in order to more closely imitate Jesus. It doesn't have to do with letting them off the hook, nor do I believe it necessarily means we expect God to judge them later.

From Matthew 18:21-22, 


  Then Peter came to Jesus and asked, "Lord, how many times shall I
  forgive my brother or sister who sins against me? Up to seven times?"
  Jesus answered, "I tell you, not seven times, but seventy-seven
  times."


Here Jesus' response was meant to indicate that our forgiveness towards each other should be endless.

And I feel more directly from John 13:34-35,


  "A new command I give you: Love one another. As I have loved you, so
  you must love one another. By this everyone will know that you are
  my disciples, if you love one another."