Focault believed a person's identity only existed in their interactions with others. We believe we have an identity because we have to talk about ourself, but in actuality there is no constant person 'essence' that remains despite time. What makes us 'us' is when we interact.
I think it's a sliding scale - some characteristics take years to change, and others depend on momentary blood-sugar levels. Mongy wonders how I have changed in one year. He's uncomfortable because i'm not talkative, not engaging, not 'here'; i appear tired, distant, and reluctant.
I'm hoping it's just perception. I'm tired at midnight because I work 10 hour days, often without a lunchbreak, days where I don't just stare at the computer but talk, interact, make decisions, instruct other, learn, exchange and must be present at all times. When I'm not at work I'm used to living alone in my head, and so when he says i'm tired and dull, I can't explain that really, I'm thinking about everything, I'm just not used to sharing it all. Who wants to hear my random thoughts as I walk along the street? And on Saturday, I do enjoy simply sitting and listening to others, but I have no desire to animate myself, no desire to network, and even very little to make others laugh. Even when I'm interested, all I want to say is 'thats great' - no need to sell my enthusiasm, I'm enthused, I promise!
There is no doubt that I am not the same person I was in Cairo last June, but have I changed enough to be an unrecongnizably different person?