Things are so hard to say...

For so many reasons, though, while you cannot truly comprehend why another cannot
stand to mention a word, phrase, or article of speech, it is possible to take slight
notice to the small things that are evident when deciding why things are hard to say. They tend to go as follows:

Embarrassment, though as simple as it may seem, this as well as the following term will coincide with the last. Embarrassment may lead to the tripping of words in the fear that one may say what others would find odd, repulsive, or unrepeatable.

Adoration, somewhat like the latter, it is a fear that what one may say could severe a close tie with one of close adoration with the speaker, and thus the words may not be possible to mention, or even whisper without the feeling of a reddening blush or rise in heart rate.

Lack of words (i.e. speechless), is the condition that arises as one is unable to counteract the discussion applied by the opposing speaker. This could be a result of joy, sadness, or anger triggered by something great enough to invoke a lack of words, or a lack of ability to conjure up words.

and

Globus Hystericus, which may be evident in any of the latter terms, as the throat constricts and creates a "lump" in one's throat.