History: Leaving out pieces of the puzzle?

People can argue of why countries leave out their "bad" times in their history books. For one, people who live in that country may be shocked or outraged that such things happened in their soil, some may be ashamed and would not like to recall those moments. With that said the governments "removes those pieces of the puzzle" to keep their people intact. So, in my opinion the government should not keep secrets from their people. For instance if I were educated all my life that our country was "guilt-free" and had no conflicts with other countries in the past then, I would visit another country, not knowing that the people there may still have hate towards my country and i would be totally confused. I would also return to my country and ask what the hell have I not been told, which could lead towards violence. So no the government should not lie towards it peoplez.