As many are talking about Sati, here am presenting the views of those who Opposed the practice Sati. The most cited person for the Opposition is Medhatithi who compared this practice as antivedic and as sucide.
Next comes BanaBhatta, the poet of Raja Harishchandra. He calls the practice as foolish followed by ignorant.
Some people try to prove that Sati is Glorified in Mahabharat, and I personally believe if any such glorification present in Mahabharat then there just interpolations. For example in southern recension of MB, we have Brhmains trying to stop the Sati of king Pandus wife.