I also think the EU definitely has issues that need to be resolved, but I would rather be in the biggest free trade sector in the world, with a say in how it works, and actually take that relationship seriously (which IMO the UK never has done, we just take what we want, and bitch about what we don't want, and complain when things don't go our way).
Instead with brexit we're likely to end up with a continuing trade relationship that costs us more and we have no say in how that trade centre works. If we had spent the time since WW2 steadily investing in our own people and infrastructure, then maybe this would be an opportunity to strike out on our own and have countries begging us for a good deal, but we haven't done that. Brexiteers will complain en masse that it's not the fault that the idea of brexit in general: being no plan whatsoever and brexiteers were duped into voting for it with promises of a moon on a stick, but it was the fault of negotiators who failed to turn a crap hand into a jackpot-winning strategy.