Why name Yitzchak after something that is perhaps negative?

Question

The episode in Bereishit 18:12-25 of Sarah laughing at the news of having a child in a year is often seen as a negative thing.

יב וַתִּצְחַק שָׂרָה, בְּקִרְבָּהּ לֵאמֹר: אַחֲרֵי בְלֹתִי הָיְתָה-לִּי עֶדְנָה, וַאדֹנִי זָקֵן. יג וַיֹּאמֶר יְהוָה, אֶל-אַבְרָהָם: לָמָּה זֶּה צָחֲקָה שָׂרָה לֵאמֹר, הַאַף אֻמְנָם אֵלֵד--וַאֲנִי זָקַנְתִּי. יד הֲיִפָּלֵא מֵיְהוָה, דָּבָר; לַמּוֹעֵד אָשׁוּב אֵלֶיךָ, כָּעֵת חַיָּה--וּלְשָׂרָה בֵן. טו וַתְּכַחֵשׁ שָׂרָה לֵאמֹר לֹא צָחַקְתִּי, כִּי יָרֵאָה; וַיֹּאמֶר לֹא, כִּי צָחָקְתְּ.‏

Why would their son then be named as a reminder of the (perhaps) negative actions of Sarah?

Answer 1

I once heard from a lecture by Rabbi Uziel Milevsky zt'l that the name Yitchak derives from his enormous awe of God and that really he is the most serious of the patriarchs. He gave the analogy, of someone afraid of a mosquito who is suddenly attacked by a poisonous snake. What happens to his fear of mosquitos? He laughs at it. it's meaningless. So too, Yitchak had such a tremendous awe of God that everything else was null and void.