We go through this discussion over and over.
We go through this discussion over and over because people like yourself are seemingly incapable of grasping what people actually write, rather than what you perceive they write.
We'll address each of your nonsensical points in turn.
Firstly cost. The GTD is £800 cheaper than the GTI. On a £25,000 car this is completely irrelevent. In the same way that you wouldnt chose one chocolate bar over another because it was 4p cheaper, you would be mad to pick the GTD simply because of the minute saving, taking into account the pricepoint. Therefore, this is a non issue.
Next, economy. You've clearly missed the main point here. He is now into his 4th month of ownership yet has not even managed go through 3 tanks of fuel. He clearly doesnt drive much, therefore any saving in fuel economy is again largely irrelevent, especially in the context of the enormous price he has paid for the vehicle and the hundreds of pounds he has thrown away by falling for junk like Autoglym Lifeshine and dealer sourced GAP insurance.
Emissions - exactly the same arguments as above. Great, 40 quid in tax a year. Useful saving to the sort of person with a £25,000 car. Not.
And now, performance. The Golf GTD and GTI are not comfortable hatchbacks. They make compromises in this area with the aim of being sporting in nature. They have stiffened and lowered suspension. They have large diameter alloy wheels with low profile tyres which will cost much more to replace when they wear out. They have sports seats which offer less all round comfort than a comfort seat but provide much better support during enthusiastic driving. As we can see, they are quite compromised in the pursuit of performance. So performance obviously matters - if it didnt, a TDI 140 SE would have been a better car to go for.
If the OP is bothered about performance, he bought the wrong car.
If the OP is not bothered about performance, he bought the wrong car.
Either way, he bought the wrong car. He probably thinks it suits his needs best, but it doesn't. Thats the problem with the general public. They always think they know best. Most of them don't have a clue.
Ironically the one thing the OP did perceive he needed - cruise control - wasn't even included on his choice of car.