My opinion is quite different to other peoples, in that I don't care too much how it affects us in the UK. At the end of the day, if leaving would benefit us a small amount economically, I don't think it's worth it. I think that, as such a well developed country, we have an obligation to stick in the EU and help the other countries that aren't in such a good situation.
If anything, that makes it more likely for the opposite to happen should we ever face difficulties. If we leave the EU, the entire burden of Europe's' economic problems falls to the only remaining "Rich" countries like Germany, and if the countries in the EU start to collapse, we will too, whether we are in there or not, because we still rely on them.
Its my belief that our planet moves forward economically, scientifically, and culturally, if we start working together more. Leaving the EU does the opposite of that to me. But maybe I'm just a hippy