Following the orders of those above you unquestionably. See, everything will go smoothly and be "harmonious."

It means to be in unison to be in agreement with one another. Or a melodious sound or chord.

In popular harmony, chords are named by their root plus various terms and characters indicating their qualities. In many types of music, notably baroque, romantic, modern and jazz, chords are often augmented with "tensions". A tension is an additional chord member that creates a relatively dissonant interval  in relation to the bass. Typically, in the classical Common Practice period a dissonant chord (chord with tension) will "resolve" to a consonant chord. Harmonization usually sounds pleasant to the ear when there is a balance between the consonant and dissonant sounds. In simple words, that occurs when there is a balance between "tense" and "relaxed" moments.

"no why, everything will be fine!"

It means NOT acting like an A*****E towards foreign expats like SO MANY Chinese DO!!!!!!!!!!!!!

Following the party line.... not to be confused with the conga line

this word "harmony" already made closely connect with china's  political and social life. about ten years ago, when president Hu announcement china should set up a "Harmony society" ,that mean all chinese people should be more peaceful and lived more comfortable with each other. BUT the truth is many local governments use this word as excuse to crack down common people's protest.   now  if  chinese people talk about "harmony society" in private, always have some irony sense in there.

Harmony means the illusion of peace and perfection in a society full of turmoil and imperfection.

Reminds me of "Manufacturing Consent".