30-second apologetics: Why do Catholics genuflect before entering a pew?

Why do Catholics genuflect (bend down on one's right knee) before entering a pew?

 We are making a sign of reverence before the Real Presence of Our Lord, Body, Blood, Soul and Divinity in the Tabernacle (meaning dwelling place):

Whenever the Blessed Sacrament (the consecrated Host) is present, we make this sign of respect as a way of acknowledging that He is really present here. 

We are not genuflecting to the altar, but rather to the Blessed Sacrament.  (However, I believe that when one passes in front of an altar, a bow is required.)

Incidentally, during the 1980's and 90's many Catholic Churches were re-designed and, unfortunately, in a misguided attempt to make the Mass more horizontally focused rather than vertically focused, the tabernacle with the Blessed Sacrament was displaced to a side altar, often away from the sanctuary.  When one enters a such a church it is often difficult to find the tabernacle.  Nevertheless, we ought to search for this hidden tabernacle and give Him an acknowledgment of His presence by a reverent genuflection before we sit in the pew!


If the monstrance 

is exposed during Adoration, the custom has been to offer a "double genuflection" that is, to kneel with both knees and bow one's head.  However, new liturgical norms state that  “a single genuflection is made in the presence of the Blessed Sacrament, whether reserved in the tabernacle or exposed for public adoration.” The rationale for that change simply was that it is the one Lord who is present in the Holy Eucharist – and equally so – whether in the reserved Sacrament in the tabernacle or in the exposed Sacrament during adoration. Thus, any distinction between acts of reverence to our Lord present in the tabernacle or in the monstrance is avoided. ...However, this does not prohibit any of the faithful from doing a double genuflection out of their own personal piety. (source)

 
Just my opinion here: when we enter a Catholic Church for a meeting we often forget that we are in the presence of the Divine.  It would be proper to genuflect towards the tabernacle (wherever it is these days!) and kneel in prayer before the speaker/meeting begins.  What a powerful witness that would be that we believe in His Presence in the Blessed Sacrament!