"I like to keep my private stuff pretty vague"

This quote by Thomas Haden Church suggests that he values his personal privacy and chooses to keep his personal life out of the public eye. He likely does not want to share excessive info about himself with others, as he prefers to keep his personal matters to himself. This might be due to a desire to preserve a sense of secret or to safeguard himself from prospective criticism or judgement. It could also be because he does not wish to be seen as an open book, and rather wishes to be viewed as a private with a certain level of mystery. By keeping his personal stuff vague, he is able to keep a sense of control over his personal life and how it is perceived by others.