They shall be holy to their God and they shall not desecrate the name of their God. (Num. 21:6)
The Torah states that Kohanim shall be holy to God and they shall not desecrate his name. This teaches us that a Kohen who falls short of holiness is guilty of desecrating God's Name. Why is it considered desecrating God's Name if one does not become holy? Surely there is a big gap between one who falls short of holiness and one who desecrates God's name?
When a manager of a baseball team is choosing players, he only chooses those that he believes have tremendous potential. The players he picks, he believes, will perform incredibly well and they'll assist the team in winning the championship. If one of the players begins goofing off it will reflect poorly on the team and on the manager. The manager needs each player to be the best they can be in their position, not merely mediocre.
So too, when God - the ultimate manager - chooses his players in this world, He only chooses those that can become great and accomplish big things. God assigned every individual a position and a mission which, if he fails to complete, reflects negatively on the whole team. A person who is merely average isn't fulfilling his mission in life, and he thereby desecrates God's name.
Every person is unique. In all history and creation there will never be two people exactly alike, with exactly the same mission. No one but me can achieve my purpose in life; no one but I can fulfill my particular part in the Divine plan. As the Mishnah in Avos states: "If I am not for myself, who will be for me?" You are not supposed to be like that guy or some other great person, rather you are to be yourself. Take all of your positive attributes and all your great qualities, and work on them until you become the best you can be.