NCed just in case I am BU. 
I work freelance and have recently taken to working in a public space. I sit at my laptop with my headphones on and occasionally get up for coffee or for the loo. I will smile and acknowledge people but don't chat. I am there for about three hours three or four times a week and have been for the past month or so.
There is a stall set up near the coffee shop on site for a well known local charity. It is an excellent organisation who do wonderful, difficult work. The stall is manned by the same chap every time I go in. His job it seems is to try to get people to sign up for a direct debit to the charity.
Every person who walks past him is greeted with a "hello love" or "alright chap" and asked if they have a minute. When they say no he is very polite and affable.
Here's my problem. I have to walk past him to get coffee, and to go to the toilet. Then I have to walk back past him again. EVERY SINGLE TIME he says hello. I say hello back on the first one of the day, smile at the second one but once it gets to the third or fourth time I avoid eye contact and try to be involved with something else.
When I was leaving today, he said hello again and I ignored him (I wasn't even near him at the time but I was the only person in the vicinity) so he shouted it across the building. At which point I scurried out.
Is it me? AIBU to want him to leave me alone? I can cope with a first thing in the morning "hello", that's just polite. But the subsequent ones feel more and more intrusive and the last one today was, I felt, a bit aggressive. I don't want to be a drama llama about it but should I say something? To him? To the charity? And if so, what?