Psychological and philosophical perspectives are employed in an exploration of the reasons particular individuals experience an activity as personally expressive while others may find the same activity neutral or even aversive. The relationships between personal expressiveness and intrinsic motivation, flow, and self-actualization are considered. The construct of personal expressiveness is shown to have its roots in eudaimonistic philosophy. Living in a manner consistent with one's daimon or "true self" gives rise to a cognitive-affective state labeled "eudaimonia" that is distinguishable from (...) hedonic enjoyment. A personally expressive personality pattern is described integrating concepts from diverse theories including a sense of personal identity, self-actualization, an internal locus of control, and principled moral reasoning. A series of empirical investigations is proposed to test the theoretical concepts of personal expressiveness advanced. (shrink)