I used to think that the bottom of the feet were more deserving of being wiped than the tops, until I saw the Messenger of Allah ﷺ wiping the top of his feet. (Using translation from Aḥmad 737)
أَنَّ بَاطِنَ الْقَدَمَيْنِ أَحَقُّ بِالْمَسْحِ حَتَّى «رَأَيْتُ رَسُولَ اللهِ ﷺ يَمْسَحُ ظَاهِرَهُمَا»