We used 3 different … [ways] to test whether the nonverbal expression of pride sends a functional, automatically perceived signal about a social group member’s increased social status.  Results suggest that the pride expression strongly signals high status, and this association cannot be accounted for by positive valence or artifacts of the expression such as expanded size due to outstretched arms. …

The pride expression is a fairly specific signal of high status. … [It] sends a message that is distinct from that of happiness,…  [and] also appears to be distinct from any message sent by anger. … The current results demonstrate that high-status perceptions of the pride expression are unelaborated and automatic. … Previous research has shown that status cues differ for males and females, and that pride recognition rates vary slightly depending on the gender and ethnicity of the individuals who show these expressions. …

The present research suggests that the pride expression functions as a unique signal of high status, and is consistent with the suggestion that pride evolved to serve this purpose. … Pride is spontaneously displayed following status-increasing events (i.e., achievement) even by the congenitally blind, who are unlikely to have learned the expression from cultural models. … The pride expression is reliably recognized in isolated nonliterate cultures.

More here.  Think of the things you do that you tend to feel proud of, and you’ll probably resist the idea that you do these things to raise your status.   In general, remembering the above result will probably make you feel awkward when you feel proud, since we tend to be prudish about admitting we seek status.

Added 11p: When people say “I’m not proud of it but …” they usually mean they don’t respect it.  People almost never respect features in themselves that lower their status, and they think features they respect should gain people status.