At Genesis 18:30, Abraham's nerve almost breaks. "Let not the displeasure of the Lord, the Lord of all the world, wax strong against me, and I will speak."
The Targum is tracking something subtle here. Each time Abraham lowers his number, he also lowers his own posture. He apologizes more. He invokes more epithets. He insists that he knows he is dust and ashes. This is the Jewish art of chutzpah kelapei shamaya — holy brazenness toward heaven — held in balance with appropriate awe.
Then comes his new offer: "Perhaps thirty who pray may be found there, ten for each of the three cities, and Zeboim and Zoar forgive them for Thy mercy's sake."
He has given up on finding a praying minyan in two of the cities. He is now asking that those two be spared purely on the merit of the other three plus pure divine mercy. He is, in effect, asking God to let righteousness subsidize non-righteousness at a ratio of 3 to 2.
And God, patient, answers: "I will not make an end if I find thirty there."
The rabbis of the Talmud preserved this scene as the template for tefillah be-ribbuy — repeated petition. Do not, they taught, assume the first "no" or even the first "yes" is the final word. Keep asking. Keep lowering. Keep pleading. Heaven is not annoyed by persistence; Heaven is persuaded by it.
The takeaway: if you are afraid you are praying too much, you are probably praying just enough.