On the US and the UK Foreign Policy

The US desire to solve world problems often compensated by their lack of understanding of how to achieve that.

The UK ability and understanding of world problems is compensated by their unwillingness to actually solve them.

This leads to various unfortunate impasse where things could not progress towards the desirable outcome. 

For example, the US Wars in Afghanistan and Iraq.

Hamid Karzai and his Northern Alliance simply tricked the US. He acted like he wants to fix Afghanistan but in reality, he was abusing the US support. Karzai and his cronies abused their power for personal enrichment and mistreated people of Afghanistan. Northern Alliance mismanagement eventually made people turn back to Taliban.

American thinking that there are good and bad guys led to this mistake. They fought to defeat the bad guys by helping out other guys, who turned out to be bad in their own way, in fact even worse than those whom their replaced. 'The worse guys' took the US for a ride and mismanaged the Afghanistan on the US watch.

Not every time worse guys win, however.

There are also times when selfishness leads to good outcomes. 

For example, greedy and selfish Spanish conquistadors who wanted to enslave locals and exploit resources of the New World, ended up destroying savage Aztec civilization that literary killed human beings in gruesome rituals as sacrifices to their gods, because they believed the world will end if they fail to appease their gods with these murders. Thanks to selfish Spanish, Mexicans no longer kill their people in ritual sacrifices.

Though what is better and what is worse is relative. Individual judgement