Elements were either retconned in later seasons or cut out/forgotten altogether

[TMC]

Josh writing for the school newspaper; Drake playing a cherry red Strat and having a female friend as a bassist in his band (they are all boys later on); Drake not having a driver's license and continually failing his test (he is driving around legally in season three without any mention of him passing his test); Josh's penchant for video gaming and talent in billiards; 'Crazy' Steve losing his job at the theater Josh works at (they are co-workers in Season 3); appearances from Josh's 'Grammy' played by Randee Heller (though she is occasionally mentioned in later episodes); Drake & Josh's juvenile criminal record from selling stolen goods unknowingly as teens (in a TV movie some five years later they are charged again as adults and given a farcical criminal trial, and no mention is made of these previous offenses); and the boys' little sister Megan keeping dangerous pet snakes in her room which terrify them (in Season 3 she instead has a beloved hamster named Herve and also a sheep she "bought off the Internet").