Looking back over the arc of my PhD I notice a similar parallel to how you feel so let me elaborate. In the first year I thought I was the shit and went around

Looking back over the arc of my PhD I notice a similar parallel to how you feel so let me elaborate. In the first year I thought I was the shit and went around feeling like I knew it all. By the end of the second year, tempered by the almost complete lack of scientific success, I felt like a loser and out of place. Then, even after a some really good results over the next couple of years, I never recovered to feeling the way I felt like in my first year: over-confident, smug and arrogant. Now, a little over four years into graduate school, and about to defend my thesis late this month, I see that I'm not a complete fool, and despite all the self-doubt and negativity I had harboured over the years, I feel a small but potent bump in my self esteem. I think that much of what I went through during graduate school was boringly human- it is, I feel, normal to be intimidated by intelligent, productive folks around you when you're not sure of your abilities and then realize over a period of time, reassured by little successes here and there, that you needn't be so harsh on yourself or think in overly negative ways. I know, boring pop psych, but like I said it is perfectly normal human to want to be better and also to blame yourself for not being as good as people around you.