I sometimes say this half in jest but do strongly believe that EVEN IF YOU DON"T GO TO THEM the type and quality of programme items will shape the atmosphere of the event and the buzz you'll get even if just socialising in the the bar. A strong and vibrant literary programme will - for example - be more likely to generate conversations of broader range and greater depth about books with your buddies (good Novacons I've had, and, indeed programmed); while decent fannish programming will energise conversations with new people from the environment you've only previously heard of by reputation (pace the last Corflu).