Oh, if you like the weeds, let me introduce you to creeping woodsorrel. It looks like small clover, grows fast and wide, has beautiful yellow flowers and when growing in open area its leaves become dark purple.
Looks great on garden paths or at the side of the concrete road. Unfortunately it likes to invade vegetable patches, or any area for that matter.

It is supposedly edible (never tried).

Last year I decided to plant the sorrel in freshly vacated flowerpot at home. It quickly jumped to other pots, took all free ground and even "invaded" curtain and ceiling (it shoots lots of tiny grains that are covered in some glue, so it easily attaches even to the window pane). It took me two months of daily weeding out every little bud to get rid of it - in the garden it is an impossible task.