Leesin, what is frustrating, is not that I think Britain will go to hell. It is an advanced nation with a lot of smart people after all. It will not be a total disaster. Most people will probably feel it a bit, but nothing spectacular. Without any qualifications whatsoever, I guess it will be a 3-5 year setback at the most.
The frustrating thing is that it was so damn unnecessary. Why shoot yourself in the foot? Sure you'll live, but this really, truly was for nothing. If you really wanted to gtfo, it would be much smarter to do so using Brexit as a leverage in negotiations. Now they have zero cards to play, they have to negotiate Brexit from a very weak position, the end result probably being a much worse trade deal, and in the long run bad for UK and bad for Europe as a whole too.
And that matters! Europe as a whole, would only grow stronger in world politics united. It would be good for Britain if Poland does well. On a basic level, this is really about the fact that we are a corner of the world that is civilized enough to cooperate, and have enough in common to cooperate. Otherwise we are subject to US, Chinese and Russian divide and conquer. The immigrants become a minor nuisance on the greater scale of things, and the influx is getting stopped (better late than never) as we speak.
Not the end of the world, but incredibly stupid and sad to see GB go.