Adam Gase has a lot of work to do. He's taking over one of the worst teams in the league, the New York Jets, who haven't played in the postseason since 2010. So, no, this isn't going to be easy, but it doesn't mean he's entitled to a long honeymoon.
For one thing, Gase is accustomed to the big chair, so there shouldn't be a pronounced adjustment period. He dealt with a lot of stuff during his three-year run with the Miami Dolphins, everything from on-the-field adversity (Ryan Tannehill's multiple injuries) to bizarre, off-the-field happenings (a cocaine-snorting assistant coach on video).