Why was Dev so disappointed and confused after his Udyapan ceremony?

Dev was deeply disappointed because he had lovingly invited Sai Baba to his Udyapan ceremony, and Baba had promised to attend. However, Dev failed to recognize Baba when he appeared in disguise. As detailed in Chapter 40, three uninvited guests, who were actually Baba and two companions, came and ate, but a "veil of Maya" and delusion prevented Dev from realizing the truth. Afterwards, feeling that Baba had broken his promise, Dev wrote a letter to Jog expressing his sorrow and confusion, stating, "I waited with great effort, but no experience came."