Just a little example, although maybe off topic a bit - when I was down at the ClassicFM Movies concert I had quite a trek and hang about to get back up here to Scotland and I met a lovely guy at St Pancras train station, who gave me directions etc and said that he loved a Scottish accent !! Anyway it was quite cold and I felt lousy to be honest, but he fairly cheered me up as he was a cheery chap himself 
. Last week travelling back the same way from the Classical Brits with the same hang around time, I met him again - it was sunny and warmish and he said I looked fantastic and brilliant 
!! I put it down to the 'Jonathan effect' as I had a great time this time round, although I think the weather helped a lot as it was nice and sunny hanging around the Stage Door this time and it was a better concert all round I thought.
I feel that meeting Jonathan does have this effect on people - he makes me smile and feel happy and good and it certainly radiates to people around you who definately notice these things and it's not just his singing that does it - it's his kind and caring personality too !! 
They should do a programme on the 'Jonathan effect' and I'm sure that they would have plenty of people to talk to about it !!
What are your experiences?