Most people, including yours truly, thought that the Shah was bad, and we needed someone/something better. Instead, we got something worse. I was a teenager at the time, and I thought wow this spiritual man (Khomeini) sounds so cool, he is so radical, and maximalist, he is the one. Pure emotions ... my father knew better than I did. This is how revolutions start, young emotional people wanting to trash everything, regardless of consequences, and getting duped by demagogues. With the hordes of villagers (mostly men) having taken over Tehran, all coming looking for work in the capital from all corners of the country, feeling lost, culturally, alone, single, furstrated ... a messianic figure promising the sky was truly a "godsend".
Most of the clerics had little knowledge of the world. Few or no citizens would send their children to the theological schools, so most of the mullahs (incl. Khomeini) were basically village people who studied theology. Their whole world was Islam, Arabic language, Arabo-Islamic causes (Palestine, etc.). Lots of incompetent people took over initially reins of power - a good example was that Khomeini's driver became head of Tehran University.
Unfortunately, their rhetorical provocations against neighbors, Israel, US, and the hostage taking, together with the purges of the army, led to all the problems that we are facing now. An Iranian who cares about his country first, and not Islam first, would not have provoked Israel and other neighbors. Israel did nothing against Iran - their problems were with Arabs - but the Iranian government made them into mortal enemies, and given their influence in the US, they have made Iran and Iranians pay heavily. However, Hating and battling Israel was not our cause - it was an Arab and pan-Islamic cause ... one that even Arabs and other muslims did not care about. Yet Iran had become more Arabs than Arabs themselves, and worse than that, the Arabs themselves did not appreciate Iran's involvement. So, we got both Israel, Arabs, and US to hate Iran ... I could go on forever but ... Iran and US could have continued a good relationship after the revolution if wiser people had taken power. Now, both countries are entrenched in their positions, unwilling to talk, with decades of mutual hostility and bitterness to back it all up. All the result of a bunch of village idiots coming to power and getting everyone upset, including both Arabs (Saddam, Saudis), Israel/USA, and even the Soviets (they placed loudspeakers at the borders right efter the revolution asking muslims there to rise up agains communist infidels).
Now, the village idiots have evolved and become much more sophisticated. For sure there have been positive things also about the lasst 3 decades in Iran, some good achievements ... but more could have been done. Mistakes made in the first few years however have caused problems that cannot be resolved ....