Chevron, Shell and BP vs the world

As a mechanic I change a fair amount of fuel filters at my job. I thought I share with the worl a pattern I noticed:

People who religiously fill their tanks in Chevron (myself), Shell, and BP and come to my shop, have the fuel filters changed, and I drain the fuel from their fuel filters have something that looks like this:

In contrast, people that put fuel, wherever, meaning, 7-eleven, Mobil, Exxon, Citgo, U-gas and repeat the procedure above have something that looks like this:

So is it worth the extra $0.10 to $0.20 a gallon? Your call :D