As is not always obvious, we know too little about certain Apostles. Simon was a "Zealot" ("Cananaean") - a nasty crowd of Jewish purists and Jude, was also known as Judas, whose name change and title, "Thaddaeus", help to distinguish him from Judas Iscariot.
So we attribute a zeal for Faith with Simon and a Catholic epistle to Jude, but they are attributions and not a true knowledge of these men who were close friends of Jesus.
Only tradition ties their deaths together and so the fact that they share a day also points to our ignorance. But unlike so many saints, we at least know their names and can invoke their relationship with Jesus to our aid.
Only John notes a request of his made to Jesus during the Last Supper: Thaddaeus says to the Lord: "Lord, how is it that you will manifest yourself to us, and not to the world?" It is a question of great present importance, which we also ask the Lord: Why has not the risen one manifested himself in all his glory to his adversaries to show that he is the victor? Why did God manifest himself only to the disciples? Jesus' answer is mysterious and profound.
The Lord says: "If a man loves me, he will keep my word, and my Father will love him, and we will come to him and make our home with him" (John 14:22-23). This means that the Risen One must be seen, perceived, also with the heart, so that God can make his dwelling in him. The Lord does not appear as a thing. The Lord wishes to enter into our lives and because of this, his manifestation is a manifestation that implies and presupposes an open heart. Only thus do we see the Risen One.
-- Benedict XVI - Wednesday General Audience, OCT. 2006