Do you ever think about what you put in your pockets?

[coffee_brake]

Actually yes, I do wear it messenger-bag style but I make the strap stitching in a style that it will hold weight, but come loose if it takes a strong pull. Like, tonight I came home with a full liter of wine (which has now been largely consumed) in the bag and that's as much as it will carry besides my wallet, but if I came off the bike, I have very un-scientifically designed the stitching at one side of the bag to not be able to withstand very strong force and tear away, making the bag (and contents) stay away from me.
Like I said, the weight of the bag sits on the seat behind me and this bag is not for long trips. It's for around town so it is not a big deal for me to reach back and adjust it to where the weight sits on the seat several times in a ride.
Long trips with heavy things require purpose-made luggage, be it tank bags, saddle bags, rear rack or rear seat, and tie-downs.

My little purse thing is made for a wallet, a hair thingie, and a few small other things you may carry for yourself or your spouse (men don't admit they wish they had purses too). But the size of the free pattern I posted also allows for a half-sandwich you couldn't finish for dinner, the mug you need to return to your buddy, your spouse's sunglasses after dark, and the day's mail. A true messenger bag carries much more, but I have real backpack I carry for that. It holds basically gym clothes and "soft" groceries (nothing in glass or cans in case I fall). The luggage rack and my typewriter case/tail bag take the rest.

Like we've all heard before, riding involves risks. Whie there is joy in completing tasks like carrying things on a bike, there is also a risk in carrying things that may cause your get-off to be a more involved tumble than it would be otherwise. The task of a rider is to mitigate the risks as he/she sees fit. I'm gonna carry both my broccoli and my spaghetti sauce home on my bike. But I'm gonna do my best to be sure something like a glass jar can't hurt me if I end up smacking into a primer-gray 1982 Cadillac that couldn't be bothered to look both ways before pulling out into the intersection.

[fishmeister]

I'll admit to having a man purse while riding.....

The guys at the corner gas station kept asking if I carry my make-up in it so I folded and quit riding with it.  

Also used to ride with a messenger case with strap to carry books to and from school.

It started feeling heavy on my shoulder when it shifted off the back seat so I ended up just strapping it to the seat.

The small backpack is pretty cool as long as it doesn't start getting filled with heavy stuff....like textbooks.