Often surprised, Velvia always surprises me with how colourful it is. I can take a shot of a sunset, and think 'this will look great on Velvia', and when I get it back (even though my composition etc. might be poor) I'm always surprised by how vivid the colour is.
Long exposures often surprise me too, sometimes due to movement in the scene (planned or unplanned) or sometimes due to reciprocity characteristics of the film I'm using.
I want to try new things and be surprised.