No, I'm not referring to occasions like this. (You wash your hands after these.) I mean something else.
You know how some employment counsellors advise job seekers to wash their hands in warm water and then dry them thoroughly just before interviews? Well I suspect that there's now a scientific explanation of a kind for this.
The psychological phenomenon that might explain the benefits of washing your hands first is often associated with Dr John Bargh of Yale and it's called priming. See if you agree with me. If you get the chance watch the BBC programme "Horizon: How to Make Better Decisions" which contains a segment about priming. If you can't do that then see the highlights here.
In essence, if an interviewer is asked to hold a hot drink before they meet a job candidate then they will view that candidate favorably; if they are asked to hold a cold drink then they will oppose hiring the candidate. Wash your hands in warm water before your interview. Don't be flushed away.