I agree in long-haul, carrying additional fuel is a serious undertaking
Do you understand the scale we are talking about in airlines like Ryanair? They have thousands of flights each day. Saving 30 kg of fuel on one flight may seem like a pittance to you compared to long haul. But say the airline does 1000 flights daily, that will mean the airline wastes 30 TONS of fuel just because their pilots 'load up for mum'.
Large airlines like Ryanair fly much more than 1000 flights...you do the math!
No wonder these airlines stress so much about the small fuel savings we can easily achieve, like taxi in and out on one engine (20 kg), delaying the engine start till the end of the pushback (10 kg), less drag approaches (20 kg). It saves tons of fuel across the fleet. Daily.
May I compliment Full Wings with his excellent post. You managed to capture the essence of a difficult (and sometime even emotional it seems!) subject.