not a daf bit

I had to miss minyan this morning for a doctor's appointment so I didn't prepare a daf bit for the congregation, but here's something my rabbi and I studied this week:

Tractate B'rachot is largely concerned with the whys and hows of prayer. The central prayer of the service, the t'filah (or amidah or shemona esrei), consists of three opening passages, some number of intermediate ones (depending on the day), and three closing ones. Each passage ends with a phrase blessing God for something specific. (That's all by way of background.)

The g'mara teaches (34a-b): these are the benedictions when one bows: the beginning and end of avot (the first passage), and the beginning and end of hoda'ah (one of the closing passages), nowhere else. Rabbi Shimon ben Pazzi said in the name of Rabbi Yehoshua ben Levi, reporting Bar Kappara: this is for an ordinary person; a high priest bows at the end of each blessing; and a king bows at the beginning and end of each. (There is some further discussion of kings.)

I knew that the talmud frowned on the often-seen practice of bowing at the beginning and end of each (and sometimes continuously). What I didn't know is the reason: it's seen here as presumptuous.