Granted that one can be obnoxious without being just, can one be just without being obnoxious?
The specific charges against "the just one" are these:
he sets himself against the doings of the wicked (v 12)
he reproaches them for transgressions of the law (v 12)
he charges them with violations of their training (v 12)
he professes to have knowledge of God (v 13)
he styles himself a child of the LORD (v 13)
his life is not like other men's (v 15)
his ways are different from other men's (v 15)
he judges the wicked debased (v 16)
he holds aloof from their paths as from things impure (v 16)
he calls blest the destiny of the just (v 16)
he boasts that God is his Father (v 16)
Which of these is optional for the disciple of Christ?
Clearly all these actions must be governed by charity, but even the confrontational ones -- the reproaches, the charges -- cannot be renounced altogether, since true charity may require such actions.
But even when the Christian is not actively reproaching others, his very life may serve as a reproach; as v 14 puts it, "To us he is the censure of our thoughts; merely to see him is a hardship for us."
So perhaps the answer is, if no one finds you obnoxious, then either you're not just or you don't know enough wicked people.