Moshe Einstadter wrote a beautiful book entitled The Yearning Soul: Essays for the Thinking Jew. He has an excellent passage regarding the idea of tocho kevaro (the ideal that one's exterior appearance reflects who one truly is inside). This excerpt appears on pages 113-114 of the work.
Incidentally, I may be many things, but I do not pretend to be what I am not. I do not pretend to like you if I hate you, I do not grant forgiveness if I have not forgiven and I have never pretended to believe in any ideology (whether it be the Agudah's or that advanced in my Sex & Gender Roles class) in order to gain favor in another's eyes. It is possible that there are those who hate me, but at least they hate me for what I am. I have never understood why one would desire to live a life reflecting values and ideals that one does not share. I believe this is my one good quality- I am stubborn, a member of the am kishei oref, and if I do not agree with you, I will not flatter you into a pretense that I do. I have lost a lot because of this but if I did not hold fast to my honesty, I would have nothing. God can see all that I am; why should I hide in the face of human censure? Of the two, I have far more to fear from- and am far more accountable to-Him. He knows the weaknesses and frailties of His daughter, the sins she has committed and the paths she has walked; He knows my reasoning or lack thereof. If I am ashamed before anyone, it is Him. God and my parents have the right to ask better or more of me. No one else.
Rabban Gamliel denied entry to the beis hamidrash to those disciples whose exterior did not truly reflect the inner person- she'ain tocho kevaro. We may translate this principle into a correspondence between chitzon and penim. The former must express the latter; anything less is untruthful.
There was a time when only those of chassidic background, abiding by the massorah transmitted by their forebears, dressed according to a well-defined code. All others, including benei yeshivah, dressed each appropriate to his station and in keeping with his individual taste. The Torah persona was evidenced by the manner in which one walked and talked and by his total deportment. This is no longer so. Today the black hat, an extensive display of tzitzis, and now, quite common, peyos wound behind the ears are the standard accoutrements of the Yeshiva man; these symbols profess, to those conversant with their meaning, that the bearer is a true ben Torah.
The abject truth is that unfortunately often they signify nothing at all. Rather than being motivated by modesty of dress, the Chofetz Chaim's strick interpretation of u'reitem oso and a halachic concern with the shi'ur of peyos, they are frequently no more than a uniform donned by members of a fraternity. It is not that these individuals are insincere, but that a chitzoniyus which ought to reflect a penimiyus hardly reflects it at all. Instaed of a foremost concern with the cultivation of the inner qualities of the Torah personality, the focus is directed largely upon the effortlessly acquired outer trappings. If the external is still meant to convey a correspondence with the inner person, then Truth is sorely compromised; and if it no longer does, then we have reduced matters of religious significance to little more than social propriety.
Am I therefore suggesting that black hats be exchanged for grey, that tzitzis be concealed; and that the length of peyos be shortened? Only an absolute fool (there are instances wherein the conceptual term "absolute" may be justly applied to the concrete) would draw such a conclusion. No, I simply decry the fact that ha'emes ne'ederes and nothing more. Blessings be showered upon the wearers of black hats- but let them not rest until they have assured themselves that were Rabban Gamliel to stand sentinel at the portal of the beis ha-midrash, he would grant them entry.