How much can you carry on a bicycle?

Mr. Homegrown read an editorial written by designer Syd Mead (Blade Runner, Tron) in which Mead badmouthed bicycles:

Mead: While the bicycle has many virtues, it also prompts people to go overboard. It’s often lauded as the transportation of tomorrow and the savior of cities. It is not. It is called transportation. It is not. That’s because the bicycle is not, strictly defined, a transport device. Ever try to carry a watermelon on a bicycle? (Yes, it can be done, but how much else could you carry?)

In response, Mr. Homegrown posted photos of all the things he regularly carries on his bike.

Mr. Homegrown: How much else can you carry on bike? On a recent trip, in addition to a watermelon, I picked up a gallon jug of vinegar, a 12 pack of toilet paper (no we have not yet switched to a corn cob on a string -- I might be the world’s smuggest blogger, but you pick your battles), 12 cans of sparkling water, a jumbo box of kitchen trash bags and a few other items.

How much can you carry on a bicycle?