The Queen incident is a classic example.
To clarify I am not talking about the way they cut the conversations etc together. Its the reaction shots that they change.
For example: Halfwit walks into the garden and Lisa is shown as scowling at him. She was actually scowling at a wasp some 5 mins earlier and had in reality smiled at Halfwit as he walked into the garden.
This would give a totally different impression of Lisa and Halfwits relationship.
If you want to know more and have 5 mins to spare then check this explanation out
http://www.youtube.com/watch?v=BBwepkVurCI