Pessimism and optimism are characteristics of sinful humanity.  The one has no confidence for the future, the other over-estimates the combination of circumstances and ability (Proverbs 27:1).  True realism demands that we know everything about every interacting person, things and event.  That is information only God holds because there is nothing He does not know about the past or the future.  In these verses, Peter overestimated his ability to remain true to Jesus, even protesting His spiritual prowess and moral courage: his optimism was a hollow shell constructed in pride (Proverbs 16:18

Jesus had chosen to do it, but He did not want to do it.  He knew the plan and had wholeheartedly agreed to die on a cross, bearing the sins of the world and experiencing the full weight of the Father's wrath against Himself.  That 'cup of God's wrath' had already been explained in the Old Testament (Isaiah 51:17), and mentioned by Jesus in Mark 10:38-39.  There was no pleasure in the 'Holy One of Israel' (Isaiah 47:4) to 'become sin for us' (2 Corinthians 5:21).  And yet He prayed in the Garden of Gethsemane that Father God would not bring Him to the hour of suffering.  Why?

The first rebuke of Jesus to His sleepy disciples (Mark 14:37-38) should have been enough to jolt them into apology, and a determination to stay awake.  Far from it!  As Jesus returned to pray, the trusted men returned to sleep.  The Master's task was unchanged, and the disciples remained unmoved.  Although He had chosen them to be with Him, they were on different tracks.  In Bible language, "They did not know what to say", meant that they knew that they had no excuse; Jesus was right and they were in the wrong.  But Satan's lies had already been swallowed and they were paralysed. 

What a sad and sick scene! Jesus, who was prepared to die for the sins of the world, was confronted by pompous religious leaders and a mob.  A pathetically unprepared group of disciples stood there limply in the darkness, while their treasurer (Judas Iscariot) feigned a loyal greeting.  As the kiss was planted the trap sprung shut.  Love had been betrayed, religious authority was unmasked as being ungodly, law had been violated ... everything true has been turned on its head.  Death was now in the air.