This e-mail is for congratulating someone for something like a promotion, great grades or something similar.
Congratulations! I wasn't surprised at all when you <description of the congratulatory event>. You've been so dedicated, so hard working, and so good at kissing up to the right people that this kind of recognition was bound to come sooner or later. But seriously, it couldn't happen to a more deserving person. Enjoy your glory and be proud of what you've accomplished. Tomorrow, you're just another grunt (just kidding). Again, my congratulations and best wishes!