Introspection is such a lovely thing. It can be internal, mental; we can reflect on who we are and what we think and why we think what we think. We can poke and prod at our thoughts and emotions, playfully or with serious motivation. Also, upon noticing our reactions to external stimuli, it can be fun to explore the extent and limits of these, and explore ourselves in that way. Sometimes it's hard to tell which we're doing; maybe there isn't even a difference.