I understand the basic gist of static electricity. Two dissimilar insulators come into contact, the chemical properties cause one insulator to "steal" some charge from another insulator. This causes one insulator to have an excess of protons, and the other an excess of electrons, and a very strong electric field. Now here is where my confusion comes into play.
In this instance, there is a major charge imbalance. Let's say Insulator A stole some charge (let's say electrons) from Insulator B. This causes Insulator A to be negatively charged and Insulator B to be positively charged, as shown in the dumbed-down image below.

After that separation, here's what I don't understand: If the electrons want to balance out, why doesn't one excess electron in Insulator A go over to Insulator B then? I understand that in real life it's usually upon a conductor that Insulator A would discharge one charge, but I don't understand why that charge wouldn't just jump back over to Insulator B, since it does want to balance out.
Also, my second question. What determines what types of objects Insulator A will be able to discharge excess charge to, or "zap"? As for Insulator B, which has an excess of protons, what type of objects will discharge an electron to it? What's the difference henceforth in the results of these two insulators - one with an excess of protons, and one with an excess of electrons - coming in contact with different types of materials?
In this instance, there is a major charge imbalance. Let's say Insulator A stole some charge (let's say electrons) from Insulator B. This causes Insulator A to be negatively charged and Insulator B to be positively charged, as shown in the dumbed-down image below.

After that separation, here's what I don't understand: If the electrons want to balance out, why doesn't one excess electron in Insulator A go over to Insulator B then? I understand that in real life it's usually upon a conductor that Insulator A would discharge one charge, but I don't understand why that charge wouldn't just jump back over to Insulator B, since it does want to balance out.
Also, my second question. What determines what types of objects Insulator A will be able to discharge excess charge to, or "zap"? As for Insulator B, which has an excess of protons, what type of objects will discharge an electron to it? What's the difference henceforth in the results of these two insulators - one with an excess of protons, and one with an excess of electrons - coming in contact with different types of materials?