When you work in an agency, you will have several clients expecting various projects and results from you on any given week. An important part of keeping your clients happy is by managing their expectations, i.e. if you can - under-promising and over delivering. Let me give you an example.
Your client has a groundbreaking (in their mind) announcement coming up in the next few weeks. The people you work with are always going to be very passionate about their business, as they should be, and every announcement will be New York Times front-page worthy to them. However, you know that this is simply not the case. When they ask about getting in a major publication for a minor announcement, should you tell them "absolutely?" No. This is the time to explain to your client a concept that is never easy to explain. Not every announcement is going to garner major press coverage. Not every announcement is newsworthy. Period.
It is extremely important that your client understands this. Otherwise, you are setting them up for disappointment, in turn, making yourself look bad. When explaining to them that this announcement likely won't generate a lot of buzz amongst the media, be ginger. You don't want to come off sounding like you don't respect or believe in their business initiatives. Something like this is a safe approach:
"While this is a major and exciting milestone for your business, it's not typically something that the mainstream, top tier media would cover. I think the best strategy is to hit the trade publications hard. That is likely where we'll see the most success."
Remember, you are the expert in your field and you need to be constantly educating your client. They (likely) don't have any PR experience and don't know the ropes the way you do.
The same strategy goes if you work in-house. Your CEO is your client, and his/her expectations need to be managed. Set yourself up for success by educating them and walking them through your decision making by pointing to examples of how this strategy has worked in the past.