There's a right way to do challenges. And a wrong way to do challenges.
The wrong way (don't do this!)
- Challenge everything. Don't challenge things that don't matter - "I think we should have this meeting at 11 instead of at 10 just because".
- Challenge loudly. Don't shout your challenge to the rafters. People are much less defensive if you talk to them one-on-one.
- Challenge rudely. Remember, you're challenging the assumption or the conclusion, not the person. So don't challenge the person.
- Gloat. The words "nanny nanny boo boo" should never escape your lips!
The right way (do this!):
- Challenge yourself. Before you go rushing around showing other people how wrong they are, challenge yourself. A successful challenger makes darn sure he's right before he goes challenging other people.
- Challenge with reasons. Bring your point to the table and also why you think it. "Gut" feelings are not god enough.
- Challenge positively. Don't say that something is wrong with the other point of view; say that something is right with your point of view.
So yeah, don't let rank rule your life. Challenge yourself, challenge your peers, challenge your boss. This can be extremely effective, as long as you're both generally correct and you're doing it with a generally positive demeanor. You know, all that standard works well with others stuff!
Good luck being insubordinate in a good way!