I truly admire weeds. I think God made weeds to show us how to be strong in the face of adversity. Think about it. Have you ever tried to pull out a weed? They have many ways of proving they are mightier than you.
Some weeds have deep roots. Plants like dandelions and Queen Anne's lace have thick carrot-like taproots, while vines like bittersweet and poison ivy boast stringy roots that spread in every direction. If you don't pull the whole root out, the weed simply grows back. And laughs at you.
Some weeds protect themselves. Aside from the itchy oils of poison ivy, some plants protect themselves with various sizes of thorns and barbs. Stinging nettle will not even tolerate a stirred leaf. Its tiny barbs really do sting. The brambles and wild roses sport various sizes of thorns.
Some weeds are prolific. I know, I know, pull them out before they go to seed. The trick is knowing when that is. Every year the garlic mustards shoot up and become seedy before I even notice them. And some seeds disguise themselves as a toy. How many pounds of dandelion fluff have been blown across my yard by a happy child? The seeds themselves are ingenious. They can be buried for years in layers of dirt and mulch and happily sprout when I inadvertently expose them to light. (This usually happens when I dig a hole for a sad shrub that will weepily wilt for a year before it decides whether it wants to live under my care.)
Please don't point out the shelves of weed killers. They deplete the soil, they are hard to isolate from the plants I like and anything with "-cide" in its name is not something I want to use where my children are wont to roll around. Besides, I am a noble gardener. I respect the strength of will in my foliaged foe. If I need to kill a weed, I will use my bare hands, as God intended. Sportsmanlike.