The reason for mentioning this Hadith in the shamaa-il is that it was not the noble habit of sayyidina Rasulullah Sayyidina Rasulullah sallallahu alaihe wasallam to wear one shoe only. If sayyidina rasulullah Sayyidina Rasulullah sallallahu alaihe wasallam prohibited others to do so, he would not practice this himself. Apparently the prohibition in this hadith is for doing so habitually. However if a single shoe is worn for a little while because the other one is torn or because of some difficulty, then there is no harm. Arising from this hadith the ‘ulama have added that , in the same manner only one khuff (leather sock) or one sleeve should not be worn. Both should be worn as is done commonly. One should keep away from cheap formalities, fashions and rudeness.