A good thing to remember is what do you want when your emotions are sparked?
A. To be comforted-do you display it, do you find that it attracts people's attention to you, when you have people's attention to your emotions do you calm down after the comfort?
B. To be left alone-do you hide it, do you find that calling attention to it only aggrivates you more.
if you choose A then that's Fe, which is calling people to attention of your emotions hence SEI or IEI
if you choose B then EII or ESI
The problem is that we all either want to call attention to our emotions and choose sometimes not to, but EII and ESI are exceptional about not calling or wearing their emotions on their sleeve.
Also, not being EII doesn't mean that you don't live your life by certain principles, but the principles that EII holds is universal, much more so then other's emphasis of personal perinciples.