[Hat tip MD with my additions]
Rav Soloveitchik (the Rav) was very meticulous and stringent in every phase of Hilchot Tefillah, the laws of prayer. He often cited the Rambam (Tefillah 5:1) that eight specific aspects of prayer must be adhered to while standing for Shemoneh Esrei. The first four are:Amidah, standing; Nochach HaMikdash, facing Eretz Yisrael; Tikun HaGuf, feet together and clean body; and Tikun HaMalbushim, proper and dignified attire.
This went to the extent that the Rav held that Chazoras HaShatz was Tefillas HATzibbur, and as such stood with his feet together facing the front. My own opinion is that this view of the Rav is even more relevant today in Shules where the majority simply cannot Daven, and are subject to a continuous set of announcements saying “we are on page number n in this edition, and page m in this edition etc”. The importance of the Shatz as being connected to and an actual Shaliach, as opposed to some performer seems to have been lost.
The Rav was once visited by a student who served in the Israel Defense Forces who asked the Rav the following question: He worked in the tank division and his job was cleaning and maintaining the tanks. Often, his uniform would get covered in oil and grime and he wanted to know if he needed to change clothing before davening Mincha. He emphasized that it would be possible to do so but it would be quite inconvenient and difficult. The Rav looked at him in amazement and said out loud,
“Why would you need to change? You are wearing bigdei Kodesh, holy clothes”!
That is how the Rav felt about someone serving in the Israel Defense Forces.