It really does depend what you're driving as to how others treat you. The wife has a mk6 GTI and I have a TTS, so I think I can see both sides of this. INMO they are both great cars that have different appeal. What I would say is that, whatever some might say, the TTS is a fantastic place to sit and the general build quality is superb. The GTI is just as good, in its own way, but you can't really compare them.
So my take on it is that, when I'm in the TTS, it's chavved-up Mk3 and Mk4 GTI's that want to have poke - usually driven by kids and usually fitted with crappy after-market xenon’s blinding everyone in sight. The next worst are definitely Beemers - why is that 3 series D's always want to try and get you to race them??? When I'm in the GTI, I find most people leave me alone but that may be because it's metallic grey, whereas the TTS is red. I reckon bright colours just attract muppets and if you're driving a decent car as well they want to have a go.
Bottom line is, every type of car has its fair share of idiots!