Have you ever noticed how ambivalent line managers are about the Human Resources function? On one hand, most of them want their HR people to be involved in key strategic decisions; on the other, they want to make sure that whatever they do is not perceived as an “HR program.” Managers often rely on their HR partners to help them build an effective team, but then chafe at them for forcing them to “follow the process.” The bottom line, as Ram Charan argued in his recent HBR article, is that many line managers are disappointed in their HR people.

While there may be many factors influencing their complex relationship, these three stand out:

First is the confusion about the role that HR is playing at any one time. As Dave Ulrich pointed out almost 20 years ago in his classic book, “Human Resource Champions,” there are actually four roles played by HR people: administrative expert, employee advocate, strategic business partner, and change agent. In some cases, an HR person specializes in just one of these roles (e.g. the manager of an HR call center is basically focusing on the administrative role). Many other HR professionals however, particularly generalists, switch back and forth between the roles, and when they (and their management partners) are not explicit about which role is being played, it creates misunderstandings.

For example, an HR person who was helping a team streamline a number of key planning activities switched the discussion from process mapping to employee performance assessment. The managers were puzzled and frustrated by the shift, because they felt that they were making progress and that HR was all of a sudden slowing them down. But the HR person was simply concerned about whether the team’s actions would eliminate some positions and wanted to make sure it was handled in a fair and equitable way. She had shifted her role from “change agent” to “employee advocate,” but because she had not been explicit about putting on a different hat, the rest of the team grew upset at the sudden change of direction. Unfortunately this happens all too often, particularly with HR generalists who play multiple roles. When it isn’t clear which role is being played at a particular time and why, managers become confused and then blame HR for not providing effective support.

Second, many managers don’t fully accept their own accountability for managing human capital, and instead want HR people to “take care of it” for them. They avoid or delay activities such as candidate interviews, performance assessments, employee feedback discussions, compensation reviews, responses to engagement surveys, and a host of others. Often this avoidance is based on a lack of time, skills, or interest – or anxiety about getting into tough interpersonal territory. No matter the reason, it leaves HR people acting like the process police and chasing after recalcitrant line managers, which does very little to enhance the relationship.

Finally, all too many HR people don’t take the time to truly understand their company’s business and the pressures facing its managers. It’s surprising how many HR people can’t explain their firm’s business model, competitive industry context, or critical product issues – much less be conversant with the key financial metrics. As Ram Charan noted, very few organizations encourage rotation between HR and line business roles; as a result, most HR people become functional or technical experts and miss out on the nuances (or basics) of the business. In the absence of this understanding, it’s often difficult for HR people to contextualize the critical human capital processes for managers, who then don’t know how to prioritize them.

The good news about these issues is that they are not impossible to resolve – although as in any two-way relationship, both sides have to join in the dance. Line managers have to accept that human capital management is a major part of their job that can’t be delegated or deferred; and HR professionals have to better understand the business and appreciate the performance challenges facing line managers. In addition, both parties need to be more explicit about what role HR needs to play at any given time.

Obviously this won’t happen overnight, but there are some easy steps that both sides can take to get started. For example, if you’re an HR manager, make a point of spending more time with business people and less with your HR counterparts. Don’t talk to them about HR, but about what they are doing in their jobs, their concerns, and their aspirations. If you’re a line manager, make sure that your colleagues in HR are engaged in your business reviews and encouraged to contribute, not just about human capital issues, but also about business decisions. If you keep asking, you might actually get some fresh perspectives.