It's very common, we're social creatures and we aim to please, especially if we perceive us not at the top of the ladder. People rather die than upset. Planes have crashed because the copilot was too polite to correct the captain. That is how powerful social pressure is.

If we live where bad feelings are not allowed we wont show them. We'd rather keep them to ourselves even if we're dying inside.

It takes a lot of courage to "be yourself".