Every Hogwarts student has been sorted into one of the four houses. For the most part, the Sorting Hat has made the correct choice. However, that does not mean that the famous hat has not made some mistakes over the years.
Due to the fact that the Harry Potter series was focused on Harry, Ron and Hermione, there was always an overemphasis upon Gryffindor. Crucially, there were a significant number of Gryffindors who – upon closer inspection – were sorted into the wrong house. Though this was partly true in regard to the other houses as well, Gryffindor was undoubtedly the house with the highest number of wrongly-sorted students.
In this sense, J.K. Rowling missed an opportunity to enrich the other houses with more prominent individuals. Even some of the most important characters in her story did not necessarily fit the criteria of the house she put them in…
10. James Potter
Correct House: Slytherin
James Potter was not heavily featured throughout the series because the bulk of the story took place long after his death. The information that was offered, however, suggested that he should not have been in Gryffindor.
In The Order of the Phoenix, Harry experienced some of the actions of his father via the Pensieve, and said actions were far from brave or noble. Purely for entertainment, James humiliated Snape without warning in front of a number of onlookers. He also had an irritating habit of showing off his Quidditch skills by playing with a recently caught Snitch.
In this sense, James was more like a Slytherin than a Gryffindor. In particular, his unprovoked attack on Snape was pure cowardice, and his constant desire to show off and be noticed suggested that he was someone who enjoyed the spotlight.
Granted, this moment was only a small snippet of James’s life, but there was little evidence to indicate that he belonged in Gryffindor based on Harry’s experience in the Pensieve.