That '70s Show - Season 4 Episode 1
It's a Wonderful Life

Eric is distraught after his break-up with Donna and wishes that they never kissed in the first place. As soon as he utters this wish, a guardian angel appears to teach Eric that its better to have loved and lost than to have never loved at all. The angel takes Eric on a journey to the future -- the 80s -- to show him how everyones lives wouldve turned out if he and Donna never got together. Eric remains unconvinced that the pain of his break-up was worth it, until the angel shows him all the wonderful memories he would have never had.