Optimism runs high this time of year. Every team has cause to believe the future is bright and anything is possible. This year's offseason "winners" like the Jacksonville Jaguars and Oakland Raiders show how even longtime basement dwellers believe in a breakout season. Maybe it will.
That aside, there's also not enough realism/pessimism this time of year — unless you read Internet comments. Every year, there are teams who fall apart for reasons both foreseen and unforeseen. Last year, the Baltimore Ravens just couldn't stay healthy. The Colts lost their star quarterback.