I certainly don't expect everyone to agree with me, but imo you have not done anything wrong until you have actually harmed another person or at least exposed them to an immediate, concrete risk. littering directly harms the environment that we all live in. leaving dirty needles on the ground is even worse than regular trash; it's a biohazard. there should be serious penalties for doing this stuff. if it's so likely that degenerate drug users are going to leave dirty needles in the street, is it too much to ask that a cop wait five more minutes to watch them do it, then lock them up (substitute whatever punishment satisfies you here)?