Who looks like me?

What is it about me that people find so familiar in someone else?

Is it a half-sibling they identify me with? Is it a cousin? A random stranger with no relation to me?

These instances stick in my memory and although I don't know the exact dates (or even year) I am listing these in roughly chronological order.

The first are before I knew I was donor conceived.

1. 1999 or 2000: Some of my work friends find a poster for a Dracula play in Fremantle Prison. The guy playing Dracula looks so much like me in the poster that you could have swapped out his picture with mine and not noticed any difference. I went to this play and seeing the actor up close I didn't notice the resemblence as much. Sadly, I got rid of the poster some years later.

2. 1999-2000: Not sure exactly when this happened but it was also at work. A guy had been out to lunch and came up to me and asked if I was just out at lunch. I wasn't. He asked if I had a brother as he had seen someone who looked just like me.

The times mentioned below are after I found out I am donor conceived.

3. 2005: My wife and I are in Albany on holiday and getting some documents witnessed by a JoP. During the meeting the JoP says I look like his son (!!). I immediately blurted out I didn't know who my biological father was and the JoP was quick to say that he wasn't the father. I explained that I was donor conceived and he said that he was not a donator and that his son is the wrong age to be my father.

4. 2007-2009: A friend of the family is over at our place and he works away in the mines. He says there is someone at his work who looks exactly like me.

5. 2011-2012: I am at a work conference which has hundreds of people attending from various stores in WA. At one point I am sitting next to some of my work colleagues that I know and two people walk past and a conversation similar to this happens:
Lady: "Why are you sitting here?"
Me: (not sure if I said anything or looked at her blankly)
Lady: (realises I don't recognise her) You're Gavin* right?
Me: No... I'm Adam.
Lady: Sure you are. Come on, you're really Gavin right?
Me: (shows name tag) No, I'm Adam, see?
Lady: Wow. You look exactly like Gavin from my store.
Me: What store are you from?
Lady: (tells me the store)

* All I can remember of the name is that it started with G. She may have said Graeme, Greg, Gavin, something like that. I have forgotten what store she was from too.

6. 2014: A few days ago at church a lady says to me that I look exactly like her friend from South Africa.

Where are you now mysterious dopplegangers?