God hates pride because it exalts the puny human being at the expense of his glory!
There are a number of instances when great and mighty men, kings in fact, reveal their pride or have it pandered to by others, and as a result, make grave mistakes and are judged:
Nebuchadnezzar in Daniel 4 who from self congratulation over his domain is reduced to eating grass as a mad outcast.
Darius who signed a law that demanded he alone be the one petitioned by anyone for thirty days and who threw Daniel into the lions den and regretted it (Daniel 6).
Herod Antipas who promised Herodias anything she wanted and ended up beheading John the Baptist (Mark 14).
Herod Agrippa, who when he gave his oration and was lauded as divine was immediately smitten by worms and died (Acts 12:22-23).
Surely God opposes the proud (” Now I Nebuchadnezzar praise and extol and honour the King of heaven, all whose works are truth, and his ways judgment: and those that walk in pride he is able to abase” (Daniel 4:37) and I Peter 5:6.