If you're a leader at any level and your people aren't challenging you, you've got to change that or you can't be a leader here because you're not going to be using ideas, you're not going to have innovation, you're not going to fully develop your people. And if you're working in a group and you don't challenge, then you're not really doing your job.
The more credible you are, the more confidence people place in you, thereby allowing you the privilege of influencing their lives.