Most of the world drive on the righthand side you may argue, so Britain (Japan, Ireland, Australia, New Zealand and a few other countries) have clearly got it wrong.
The decision to drive on the left comes from medieval times when jousting was done carrying the weapon in the strongest hand (being the right hand) meaning the horses needed to pass to the lefthand side of each other. Any good jouster or sports person should know that. Take football (aka Soccer). Most people are right footed and if you want to kick the ball properly you need to move to the left of the ball in order to kick it.
You may argue that very few people joust nowadays, cars have replaced horses and sports have nothing to do with driving on the road. That’s fair enough, so let’s consider one last thing:
In Britain, the steering wheel is on the right side and the opposite of right is wrong. It’s now clear that many countries have steering wheels on the wrong side after all.
Either way, driving on the left isn’t any more daunting and it shouldn’t put you off a tour of the British Isles for your next break. Campervans and cars can easily be rented. Horses are harder to come by.