She turned to leave and saw someone standing there. It was Jesus, but she didn’t recognize him. “Dear woman, why are you crying?” Jesus asked her. “Who are you looking for?”
She thought he was the gardener. “Sir,” she said, :if you have taken him away, tell me where you have put him, and I will go and get him.”
“Mary!” Jesus said.
She turned to him and cried out, “Rabboni!” (which is Hebrew for “Teacher”). John 20:14-16

Emotion, stress, diverted attention, and many other things can keep you from seeing and recognizing the obvious.

I remember the time I was riding a bicycle and a cat jumped out in front of me and started running. I began peddling faster trying to catch the cat, which was right in front of my wheel.
I failed to see the car until the cat ran under it and I slammed into the bumper.
My attention was so intense on the cat that I did not see the danger.

Such is the case of Mary. She was so intent on finding who had taken her Lord that she did not see her Lord.
Nor did she recognize the angelic nature of the two in the tomb in the previous verses.

There are many people today that fail to see just who Jesus is. They do not recognize the Creator, Savior, Messiah, Lord of Lord, and King of Kings.
What is even more sad is that many of His own followers do not see Him and know Him for who He is. To them He is nothing more than an escape from hell or a good person. To them He may be the risen Savior but He is not the living Lord to reign in their lives.

In our scripture, Mary did not recognize Jesus when He spoke. She only recognized Him when He called her by name.

Saul (Paul) on the other hand, was called by name first and did not recognize Jesus until he was told who He was!

Today, ask the Lord Jesus to reveal Himself to you in such an undeniable way that you wil have no other choice but to draw closer to Him.
God chose him as your ransom long before the world began, but he has now revealed him to you in these last days. Through Christ you have come to trust in God. And you have placed your faith and hope in God because he raised Christ from the dead and gave him great glory. 1 Peter 1:20-21