The man in today's Gospel reading told Jesus that he had kept the commandments since his childhood (Mk 10:20). So Jesus gave him five more commandments: go, sell, give, come, and follow (Mk 10:21).
The man refused to obey these commandments. Immediately, his face expressed his rebellion. The verse describing his reaction can be translated: his "face fell" (Mk 10:22). Some of the connotations of the Greek word are: the man glowered; his face became overcast, expressing even tinges of hatred.
To obey the Lord is delightful (Ps 40:9). To disobey the Lord is hateful, depressing, and sad (see Mk 10:22). To obey God's will is our food, nourishment, and fulfillment (Jn 4:34). To disobey God's will is emptiness and desolation. To obey the Lord is to enter into the Lord's love and intimacy (see Jn 15:10; Mk 3:35). To disobey the Lord is to become alienated and isolated into an everlasting hell of narcissistic selfishness.
Let us follow Jesus by obeying Him even to death on the cross (Phil 2:8). Then we will be exalted with Him forever.