According to Trinitarians, why does Jesus glorifying himself amount to nothing?

John 8:54-55 has Jesus saying > "“If I glorify myself, my glory is nothing. It is my Father who > glorifies me, he of whom you say, ‘He is our God,’ though you do not > know him. But I know him; if I would say that I do not know him, I > would be a liar like you. But I do know him and I keep his word." For unitarians, this makes sense - Jesus is a man, the Father is God, and so what is important about Jesus is that the Father (= God) glorifies Jesus, not that Jesus might glorify himself. For Trinitarians, why would Jesus, who is God, glorifying himself be 'nothing'?