id rather step on a big one than a small one. the smaller they are the more dangerous.
That's a generalization that doesn't really have much validity to it. If we compare a small and large scorpion of the same species, the larger one will have MORE venom to deliver than the small one. Sure, the smaller ones aren't adept at gauging threats, but the larger ones only regulate venom used in their prey, using only the minimum required dose because venom is expensive to produce, in terms of biological activity and resources.
EX: a scorpion takes a nap in your shoe, and you put the shoe on. Your big, sweaty, smelly toe gets all up in that scorpion's face, and that scorpion gets defensive. The bigger the scorpion, the more venom.