From what I see around the world for democracy to work it needs a certain degree of social cohesion, which some countries lack. The prevalence of some characteristics (ex: fanaticism, tribalism, corruption) are incompatible with democracy, and will ruin shortly attempts to have "working democracies".
Some western countries (not all, guess is obvious who :-p) tended to think simplistically that if the system works for them it will work for everybody so they try to "impose it".
What I have to admit now is that while this does not seem to always work, I don't consider "others" as having a much better alternative either.