I exude purpose and joy.

Nobody exudes anything on purpose. It's a byproduct, and any attempt to produce it directly is visible from across the room.

What actually reads as purpose is much plainer: someone talking about a thing they genuinely care about. The pace changes, the hands start moving, they forget to be self-conscious for ninety seconds. It makes no difference whether the subject is stochastic modelling or canal boats — the effect on the listener is identical.

Joy follows attention far more reliably than it follows effort. Find the subject that does that to you and spend an hour inside it this week. Other people will notice something, and it won't be the hour.