First we must clarify what the background to the information is.
Let's see how God interacts with all people.
God places people in different situations causing them to be disturbed.
Acts 17:24“The God who made the world and all things in it, since He is Lord of heaven and earth, does not dwell in temples made with hands; 25nor is He served by human hands, as though He needed anything, since He Himself gives to all people life and breath and all things; 26and He made from one man every nation of mankind to live on all the face of the earth, having determined their appointed times and the boundaries of their habitation, 27that they would seek God, if perhaps they might grope for Him and find Him, though He is not far from each one of us;
People get upset because they are forced to life selfishlessly or in order to survive, contrary to what their consciences tell them.
Most people give up and join the darkness, because they think there is no other choice.
However some people won't compromise, they won't adapt, or make permanent changes to settle in the world system. They grope around, seeking for God. God is not ashamed to be their leader and promised to make a better humanity, city, country for them to occupy, Rest in. They are clean believers, have been baptised into water.
Hebrews 11:14For those who say such things make it clear that they are seeking a country of their own. 15And indeed if they had been thinking of that country from which they went out, they would have had opportunity to return. 16But as it is, they desire a better country, that is, a heavenly one. Therefore God is not ashamed to be called their God; for He has prepared a city for them.
God gives them to Christ, which is metonymy for sanctification. They are given access to drink from the Rock. This means they experience situations where they face danger and are rescued by God, like Abraham, and Israel in the wilderness, to increase their faith. Because they must learn that they can enter the Kingdom of God, where a person can live selflessly and survive. Abraham learned this unlike Israel, and he also intuited that by living selflessly and surviving, others would see the great works of God displayed and be motivated to turn away from selfishness and serve God through selflessness. That is why he obeyed when asked to sacrifice Isaac. He believed God would do a great work and return Isaac to him.
1 Corinthians 10:1For I do not want you to be unaware, brethren, that our fathers were all under the cloud and all passed through the sea; 2and all were baptized into Moses in the cloud and in the sea; 3and all ate the same spiritual food; 4and all drank the same spiritual drink, for they were drinking from a spiritual rock which followed them; and the rock was Christ. 5Nevertheless, with most of them God was not well-pleased; for they were laid low in the wilderness.
This is how believers can enter Rest, the New Humanity in Christ, be a blessing to the world while resting from their own efforts.
So when believers partake of the Holy Spirit, which means living selflessly, picking up or crosses, and being raised up, and receive fire, the ability to decipher very complicated information of the Scriptures, people see the great works of God displayed.
This is because believers are baptised into the Holy Spirit and fire, miracles and revelations, when they become clean, leave selfish living. Christ washed their feet, baptised with the Holy Spirit and with fire, empowered believers with miracles and revelation. The wrong teachings of the Pharisees, chaff was burnt way, with only correct teachings being retained:
Matthew 3:11“As for me, I baptize you with water for repentance, but He who is coming after me is mightier than I, and I am not fit to remove His sandals; He will baptize you with the Holy Spirit and fire. 12“His winnowing fork is in His hand, and He will thoroughly clear His threshing floor; and He will gather His wheat into the barn, but He will burn up the chaff with unquenchable fire.”
Let's come to the question, "Did Jesus teach that servants are not to be thanked? ", we must understand that the disciples had asked for their faith to be strengthened, they wanted to see more of the Father and His works, listen to great revelations of Scriptural teacings. Jesus calls this "giving servants their food".
The point is that they had had their bodies bathed and their feet washed. They were clean, were in the Kingdom. They already had enough faith to move mountains. Now it was their turn to "serve". They had no right to ask to be served "bread"! Their job description was to serve "bread from heaven" to the world, be a blessing to others, increase others faith by expressing their own faith, displaying God's great works, when they picked up their crosses and were rescued!
They couldn't ask for food. They couldn't even expect praise any more, for serving others what they had received.
Matthew 16:15He said to them, “But who do you say that I am?” 16Simon Peter answered, “You are the Christ, the Son of the living God.” 17And Jesus said to him, “Blessed are you, Simon Barjona, because flesh and blood did not reveal this to you, but My Father who is in heaven.
All Scripture from the NASB.