Our Rabbis taught: The generation of the flood became arrogant only because of the goodness that the Holy One, blessed be He, lavished upon them. They said, "Do we need anything but a drop of rain? We have rivers and springs from which we supply ourselves." The Holy One, blessed be He, said, "With the very goodness I lavished upon them they provoke Me; with it I will judge them," as it is said, "And behold, I, even I, am bringing the flood of waters" (Genesis 6:17). Rabbi Yochanan said: The generation of the flood corrupted with abundance [be-rabbah], "And the LORD saw that the wickedness of man was great [rabbah]" (Genesis 6:5); with abundance they were judged, "all the fountains of the great [rabbah] deep."
The Generation That Boasted It Needed No Rain
Yalkut Shimoni on Torah 58:1
תָּנוּ רַבָּנָן, דּוֹר הַמַּבּוּל לֹא נִתְגָּאוּ אֶלָּא בִּשְׁבִיל טוֹבָה שֶׁהִשְׁפִּיעַ לָהֶן הַקָּדוֹשׁ בָּרוּךְ הוּא, אָמְרוּ, כְּלוּם אָנוּ צְרִיכִין אֶלָּא לְטִיפָּה שֶׁל גְּשָׁמִים, יֵשׁ לָנוּ נְהָרוֹת וּמַעְיְנוֹת שֶׁאָנוּ מִסְתַּפְּקִין מֵהֶן, אָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא, בַּטּוֹבָה שֶׁהִשְׁפַּעְתִּי לָהֶם מַכְעִיסִין אוֹתִי, בָּהּ אֲנִי דָּן אוֹתָן, שֶׁנֶּאֱמַר "וַאֲנִי הִנְנִי מֵבִיא אֶת הַמַּבּוּל מַיִם". אָמַר רַבִּי יוֹחָנָן, דּוֹר הַמַּבּוּל בְּרַבָּה קִלְקְלוּ (שם ה) "וַיַּרְא ה' כִּי רַבָּה רָעַת הָאָדָם", בְּרַבָּה נִדּוֹנוּ, "כָּל מַעְיְנוֹת תְּהוֹם רַבָּה".