Uhhh, because like, uuuhhh the reason that I very plainly and Nicely stated directly above you. Don’t be childish and pull the mocking making fun of routine. Do some research and realize bike crashes/falls aren’t even close to a large percentage of TBI(traumatic brain injury) patients and your mom didn’t kniw what she was talking about when she taught you how important it was. That or make sure you’re out making fun of everyone else who engages in activities daily that are statisticslly much more risky and they “should” be wearing a helmet for. 🙄