Is it just me or do you get out the car smelling of exhaust fumes?

I've checked all the exhaust elbow's joints, downpipe etc and can't smell any leaks in the engine bay. Almost appears to be coming from the rear of the car, into the boot then in the cabin. I've tried to block the 2 vents either side which improves things.

Am I being too paranoid and overly concious about my health or is this the norm and should I quit whining?

Mongoose turbo back 3" system into a 4" tailpipe.

Cheers