My experience of grad school was that first & second year students tended to have an inflated sense of their own abilities - they had tended to be the smartest

My experience of grad school was that first & second year students tended to have an inflated sense of their own abilities - they had tended to be the smartest kid in their classes in school & university and it took a year or two for the arrogance to wear off when hit with the realities of actual research work. Not always, but more often than not.