My Thai is poor, but when people see me they say something like "papa a bore, I thought it was a complement!

That's a good point that it makes a big difference about the age of the person calling you Papa. I haven't really been taking a survey of that. I will pay more attention as I walk down the Papa road. (Beats the alternative.)

I am being called something along the lines of "paw gnai"- anyone know what that means?

It could be pu yai,or pun yai,i get called that it by some of my family sort of means older man,but like sort of older boss man,the Guvnor,sort of think i think ,well i hope,any way thats what i reckon they are calling you,it is quite good i think.

OK, I'm screwed now. Last night a bike taxi guy who looked about 80 said you want taxi Papa?

I don't think the term 'papa' is used where I live, at any rate I've never noticed it.

Where I live, people use the term 'leung' or 'uncle' to describe older men.

Once, while riding on a rickety old inter-city bus, a little boy stuck his head over the seat back in front of me and asked, "Where are you going, Uncle? The boy's mother kind of cringed in embarrassment and shushed him, but then all the passengers within earshot started laughing. I always assumed that the reason people found this funny was because, even though to them I didn't look old enough to be called 'leung,' the little boy clearly had a very different perspective of my age.

I was only in my early 50s at the time.