לְהָבִיא אֶת וַשְׁתִּי הַמַּלְכָּה לִפְנֵי הַמֶּלֶךְ בְּכֶתֶר מַלְכוּת לְהַרְאוֹת הָעַמִּים וְהַשָּׂרִים אֶת יָפְיָהּ כִּי טוֹבַת מַרְאֶה הִיא.
Why does a man want a pretty wife? So he can be attracted to her and enjoy looking at her. So why does Achashveirosh need to show Vashti's beauty off to everyone else?
THAT is a person who is empty inside and needs validation from others.
Most are us are little Achashveiroshes in some way. We are not happy with who we are, what we have or what we have achieved, unless other people know about it and appreciate it....