I heard in the name of Rebbe Elimelech that if a person wishes to rise higher in his spiritual level, he must see to it that his character traits are whole and perfect on the lover level. This is because it is impossible to maintain a constant static level. A person is like the angels called Chayos, which run and return, for sometimes he rises, and sometimes he falls. And if his lower levels are not perfected, how can he return to them? The Rebbe compared this to a man climbing a ladder. The wise and intelligent man will first test all the rungs to make sure that they are whole and intact so that if needs be he can retrace his steps and return to them. MiPeninei Noam Elimelech, Shemos
Daily Halacha 24, 25 Teves
During Kedushah, Neias Kapayim - It is strictly forbidden to talk Total concentration is mandatory.
Between Chazaras ha- Shatz and Tachanun It is inappropriate to talk; there should be no interruption between Shemoneh Esreh and Tachanun.
Between Tachanun and Kerias ha-Torah- There is no specific prohibition against talking.
During Kerias ha-Torah- It is strictly forbidden to engage in either idle talk or divrei Torah during Kerias ha-Torah One who speaks at this time is called "a sinner whose sin is too great to be forgiven. Some poskim probit talking as soon as the Torah scroll is unrolled".
Between Aliyos- Some poskim prohibit taking totally. Others permit discussing divrei Torah only, and others are even more lenient.
During the Haftarah and Its Blessings - It is forbidden to talk as one must give undivided attention to the Haftarah reading.
Between Kerias Ha-Torah and the end of davening, There is no specific prohibition against taking.
During Hallel, It is forbidden to talk. Doing so constitutes an interruption of Hallel.
During Vayechulu and Magen Avos, It is forbidden to talk.