Why is Iran bombing civilian targets in friendly countries?

Since the war started, Iran has been using missiles and drones against civilian targets in neighboring countries. They've hit a hotel in Bahrain, a residential neighborhood in Saudi Arabia, the airport in Dubai, and others. Even desalinization plants, which some countries depend on for survival.

I can see why they'd shoot at Israel or at American bases in Gulf countries. But why so many civilian targets in countries that are not involved in the war and are the closest thing Iran has to allies?