The more you know, the more you know you don't

The best thing about being a research student is that you get to discover and explore new things. What I mean 'new' here doesn't always refer to great science discoveries. It can be just discovering and understanding more about oneself. How you behave under stress, or what's your limit and potency. Sometimes, it can also be about how much you really have mastered a particular knowledge or skills to be known as an expert. But for me, it has always remained a wonderful experience to know how much I don't know and how much I could improve from there, or to refresh something that I've long forgotten or never pay much attention (especially when I have to answer questions from undergrads). If research life is really that tough, this at least is the satisfaction that one gains along the journey.