Be specific: Before expressing appreciation to someone, think about what specifically you appreciate about what they said and did. Doing so will illuminate what you value.
When we are not specific ("you are terrific, Jorge. You really are a team player") the other person defines the appreciation through the lens of his own values. There are many definitions of a team player: someone who helps others when he has down-time or subordinates his goals for those of the team. Perhaps it is someone who supports the team's ideas to the higher ups even when he disagrees with them.
When the boss uses vague praise, Jorge will continue doing whichever behavior he deems demonstrates team playing. Others on the team will chase after their own ideas, always wondering why they are not praised, secretly suspecting that the boss just likes Jorge best.
Use specific language to define the behaviors or outcomes you appreciate so that the other person knows exactly what he did that matters to you.
Example: "Jorge, thanks for supporting the team by traveling to the client site to fix the problems. I know you didn't create those problems and had to put up with a lot of the client's mis-directed anger. You made the team look good and saved our relationship with one of our key clients."
Adapted from: The Seven Languages for Transformation: how the way we talk can change the way we work, by Lisa Lahey and Robert Kegan. (c) 2001 Jossey-Bass.