I don't think lying is always wrong.
I don't think it's ok to lie to someone if it was important.
When Peeta said he liked Katniss. The Careers lying to Peeta to make him think that he's with them but they are just using him to find Katniss. When Effie tells them to have a different personality just for that time. When Katniss lies that she doesn't know the Avox Girl.