Having so much godly power that you just don't care anymore. Fighting the most powerful beings is boringly easy and you don't care enough to give them a fighting chance. You just want it to be over.
"Abby has such a SaitamaComplex when she plays Skyrim. She just doesn't give a shit."
Being levels above other people to the point you are unbeatable. Your interest/hobby that you have become so strong in is a bore; you actively seek challenges and are desperate when it comes to someone opposing.
"That new anime character has a Saitama Complex. He's insanely strong but he finds nothing entertaining anymore. Although, it's a great show to watch because not many people can pull off having a Mary Sue character."
A very good example of a Telegram Group management bot which is made by Sawada.
It is basically a modular Telegram Python bot running on python3 with a sqlalchemy database and an entirely themed persona to make Saitama suitable for Anime and Manga group chats.
The bot also has a jealousy feature which causes others to shitpost about the bot.
Person 1: Hey are there any bots which are underestimated but are insanely awesome Person 2: Ever heard of Saitama Robot?
Person 1: Ah that bot that's op but retards don't wanna admit it