The sting from a dead wasp can be worse than from a live one. You step on it, its stinger goes into your foot, then you proceed to squish the wasp which forces a large amount of poison into your body. I’ve done this, but fortunately I’d developed a mild immunity to their poison after a particularly bad incident in which I was stung well over 100 times within a couple minutes when I was 9, though I’ve heard that such things usually results in an increased sensitivity.