I hope in some way I can show you some of the exciting things in this verse that have inspired and encouraged me.
First, Jesus was looking far, far ahead as He prayed. He certainly prayed for the many people who sincerely believed in Him and followed Him in His earthly ministry. Remember, there were "many" disciples beyond the original twelve. But Jesus prayed for the many millions who would believe on Him in the centuries to come. This is one of the clearest verses you will find in Scripture where you and I are included in Jesus' thoughts and prayers! Maybe that doesn't "hit you" as much as it does me, but I see a very personal prayer Jesus prayed. His requests in this prayer were not just for a "crowd" of people. In His own omniscient and omnipotent way, Jesus prayed for every last believer in verse 20!
Second, Jesus knew we would respond to the word preached starting with the ministry of His apostles and the many other disciples who "went everywhere preaching the word." Acts 8:4. And that word is continuing to be preached today and you and I have a part in that preaching! Jesus knew we would also carry the message to the lost!
Third, I get excited every time I hear of someone coming to know Christ. I have a lot of missionaries I pray for and I'm always thrilled with the reports of people getting saved all over the world! I can see the prayer request of John 17:20 being answered almost every day!
That blesses and encourages me a lot! Hope it does the same for you, too!