Both the nagger and the poker player might eventually confront the person they have a problem with, but often it will be in an unproductive outburst that does not lead to any change of behavior and probably deteriorates the relationship.
Whether you can tell someone that you want them to change their behavior and still maintain a good working relationship with them or not depends on several factors. For example, the ability of the other person to receive feedback, their particular personal history and their history with you, and your own capacity to manage your own emotions if the conversation does not go your way. However, there is a part that is completely under your control which is what I want to address in this post.
When I teach communication classes I always tell my students that before getting into the conversation they have to have two things very clear . One is, what are their needs and two, what concrete actions can the person they are addressing take (or stop taking) to meet those needs.
The importance of knowing your needs or motivations allows you to gain some perspective about who is the person that is most appropriate to ask and gives you clarity on what kind of action you would like this person to take.
So for example, let’s say hypothetical John has not returned your e-mails for status of the project leading up to the meeting. If you need to know his project status so that you can communicate with a client, maybe you only need a timeline from John. You may also need reassurance that he is in the same page as you, in which case maybe what you need is for John to describe to you the end result of what he is trying to accomplish.
On the other hand if what you need is to trust that John will answer emails in a timely manner, you might want to know what was going on that prevented John from answering you, check in with him about how it affects the rest of the team and/or for him to make the commitment to change his behavior. If this is a repeated occurrence, maybe you will need support from another team member in receiving information about John's projects.
To ask for what you want implies some level of vulnerability on your part. You need to express your motivation or need and then follow it with a clear request. The trick is, you don't know if the other person will agree to do what you ask, or, even if they do agree, they may or may not follow up in terms of action. It is that vulnerability that can bring connection to the interaction because you allow the person to know where you are coming from, and can open an opportunity to reach a solution.
If John does not know why you keep asking for project updates and then you express your displeasure, maybe even in an indirect manner, he might start labeling you as a control freak. John does not have more information from you, he does not know your need beyond you wanting him to give you the status of his work whenever you ask for it.
From the perspective of John, you are just complaining. A colleague used to say, there is a good reason why Martin Luther King’s speech was called “I have a Dream” and not “I have a Complaint”. People are not inspired by complaints, and mostly just want to stay away from you.
So to make sure you express what your need and be specific and clear about what action you want the person to take or stop taking. Don't be a nagger. Put your cards in the table and keep the poker game out of your business.