Whenever Marvel heroes find themselves on an alien planet or transported to another time they often take it upon themselves to interfere in a situation without first gathering all of the facts or considering the greater consequences of their actions. This is usually shown working out for the best, but has a situation ever occurred where it was later found out to be a complete disaster. Maybe the dictator that was oppressing the people was necessary to prevent a worse evil? Have the Fantastic Four or X-Men run into a problem like this?
Best example I can think of right off hand is one time She-Hulk battled a Badoon whom she thought was wrongfully attacking some gamma being from another planet. Turned out said gamma being was a wanted criminal and the Badoon was a lawful bounty hunter not trying to hurt anyone else. The criminal murdered several members of a family before it was stopped.
Anything similar happen for any of the heroes, but on a much larger scale?