Not putting too many eggs in one basket
I see this every season, and every season I watch someone lose because of it. While it is important to look at top offenses for players on your team, limiting how many from each team is vital to your success. When owners find themselves having too many playmakers from one team, that owners team starts relying solely on the success of that team.
For example, in 2016 there was a player that drafted three Dallas Cowboys players. They had Dak Prescott, Ezekiel Elliott, and Dez Bryant. During the regular season, he dominated with big game after big game from all of these players. Unfortunately for him, the team limited their star players in the later weeks of the season since they were already guaranteed a playoff spot. Which means when it was most important during the fantasy football playoffs, guess who couldn’t recover when his top three players were all on the same team.
Another example would be last season we had a player that drafted both Randall Cobb and Jordy Nelson. While both are good players and have one of the best quarterbacks throwing to them, guess who fell toward the bottom of the rankings when Aaron Rodgers got hurt. He put too many eggs in one basket and his team dropped dramatically from an injury that wasn’t even his player.