Moses remained there on the mountain with the Lord forty days and forty nights. In all that time he ate no bread and drank no water. And the Lord wrote the terms of the covenant—the Ten Commandments—on the stone tablets. Ex 34:28

It is no wonder that Moses was such an awesome man of God. To fast is one thing but to do it in the presence of God is something else altogether.
Add to that the Creator writing the Covenant.

You would think this would be a life changing experience – and it was. But other factors ruin the God experience, like other people.

Soon the people began to complain about their hardship, and the Lord heard everything they said. Then the Lord’s anger blazed against them, and he sent a fire to rage among them, and he destroyed some of the people in the outskirts of the camp. Then the people screamed to Moses for help, and when he prayed to the Lord, the fire stopped. Num 11:1-2

Moses heard all the families standing in the doorways of their tents whining, and the Lord became extremely angry. Moses was also very aggravated. Num 11:10

While they were at Hazeroth, Miriam and Aaron criticized Moses because he had married a Cushite woman. Num 12:1

Then the whole community began weeping aloud, and they cried all night. 2 Their voices rose in a great chorus of protest against Moses and Aaron. “If only we had died in Egypt, or even here in the wilderness!” they complained. “Why is the Lord taking us to this country only to have us die in battle? Our wives and our little ones will be carried off as plunder! Wouldn’t it be better for us to return to Egypt?” Then they plotted among themselves, “Let’s choose a new leader and go back to Egypt!” Num 14:1-4

Moses may have stood and fasted before God but it was the moaning, groaning, and bitter complaining of the people that led him to take his eyes off God and commit a grievous mistake.

Then the glorious presence of the Lord appeared to them, and the Lord said to Moses, “You and Aaron must take the staff and assemble the entire community. As the people watch, speak to the rock over there, and it will pour out its water. You will provide enough water from the rock to satisfy the whole community and their livestock.”
So Moses did as he was told. He took the staff from the place where it was kept before the Lord. Then he and Aaron summoned the people to come and gather at the rock. “Listen, you rebels!” he shouted. “Must we bring you water from this rock?” Then Moses raised his hand and struck the rock twice with the staff, and water gushed out. So the entire community and their livestock drank their fill.
But the Lord said to Moses and Aaron, “Because you did not trust me enough to demonstrate my holiness to the people of Israel, you will not lead them into the land I am giving them!” Num 20:6-12

Moses cannot use the complainers as an excuse for his problems. Sure, each of us must deal with others and that can sometimes be a problem. But each of us are responsible for how we react to others.

Will you let the actions, words, or attitude of another person get between you and God?

Set your mind on things above, not on things on the earth. Col 3:2