Only if you have a terrible management culture.
Even great managers make mistakes, and it takes courage to speak up in such circumstances. A good boss will sometimes push back very hard, so as to gauge your commitment to your position.
BOSS: "Here is my plan, I need you to execute it."
OPTION A:
ME: "I will not, this plan is bad for the company."
BOSS: "OK, we'll come up with another plan."
OPTION B:
ME: "I will not, this is a bad plan."
BOSS: "I disagree, do it anyway."
ME: "I'm very serious."
BOSS: "OK, we'll come up with another plan."
OPTION C:
ME: "I will not, this is a bad plan."
BOSS: "Do it anyway."
ME: "No."
BOSS: "Do it, or you're fired."
ME: "Let's take this to the VP and let them decide."
BOSS: "...what was your plan again?"