Maybe because of this irritation you aren’t as nice to her as you should or could have been.  Maybe you’ve tried to use your position in the organization to “win” a power struggle.  Now, you’ve noticed that every time you want to get an appointment with the CEO it seems that the secretary isn’t able to fit you in, or maybe your expense reports are coming back as timely as they used to.  To add insult to injury you have now noticed that the CEO isn’t as friendly to you as he/she once was. 

The cold hard truth is that if someone in the organization has an executive’s ear, you’d better be just as cognizant of how you treat that person as you are of how you treat the executive.  I’d argue you should be nice to everyone whether or not they have informal power, but that’s a different blog.  If you are managing an employee who has informal power, make sure you leverage that to your benefit.  Don’t ignore it, use it if you can.