Well, at some point I hope to visit both North Korea and Iran. Presuming the situation is similar to today's, North Korea shouldn't be too hard since they only REALLY hate South Koreans, Americans and Japanese. Most other nationalities, they may not actively like, but with a British passport, I shouldn't' have any trouble.
On the other hand, Iran may pose a problem. Though there aren't any official blockages, and the Persian people are supposed to be some of the nicest and westernized in the Middle East, the fact that we still don't have an embassy due to it being attacked is a cause for concern. But, I have devised a plan to make this easier. Since my late grandfather was Irish, my mum is able to easily register for an Irish passport, which will enable me to do so as well. Since the only area of the world that has anything against the Irish is Northern Ireland, I'm pretty much safe no matter where they go.
A while back, my dad said something. If I get kidnapped in a Middle Eastern country, first they execute the Israelis, then the Americans, then the British/French/whoever the big bad of Europe is at that time. Ireland i a long way down on that list.
Also, it'll make journeying to both Israel and the Lebanon a lot easier with two passports of different nationalities.