In my experience, I tend to feel insecure about simply mouthing off emotionally at something without giving logical reasons, so I tend to detach and try to not let anything get to me, but then when I try to be "logical" or what have you, I end up fumbling for words, speaking slowly, and appearing to lack confidence. That's why Te is so important, as it justifies to me these internal Fi states that I otherwise feel like I need to defend using Euclidean logic.