As far as MLB is concerned, winning percentage doesn't really enter in to whether a team makes the playoffs or not. A team makes the playoffs by winning their division or being the team with the highest winning percentage of those other teams that did not win their division. There have been teams to make the playoffs with a record as 'poor' as 83-78, as did the 2006 St. Louis Cardinals who went on to…
The term spoiler is most often applied to the team which has nothing to gain from the outcome of the game but can adversely affect its opponent's position by winning the game. For example, if team A has already been eliminated from the playoffs but team B must win the game in order to avoid elimination from the playoffs, then team A is called the spoiler if it wins the game.
The NFL team that has been to the playoffs the highest number of times is the New York Giants, with 32 times. They have made it to the Superbowl 5 times, and won 4 times out of those five. Their wins were Superbowl XXI against the Denver Broncos, Superbowl XXV against the Buffalo Bills, Superbowl XXXVI against the New England Patriots, and Superbowl XLVI against the Patriots.
There are four teams from each league that make the playoffs. Each league is divided into three divisions. Each division winner gets an automatic bid to the playoffs. There is a fourth team from each league that makes the playoffs and this team is called the 'wildcard' team. The wildcard team is the team that has the best overall win loss record of those teams that did not win their division.
Eight. Four teams make the playoffs in each league. There are three divisions in each league and the three teams that wind up in first place in their division make the playoffs. The fourth team to make the playoffs is the team that did not win their division but has the best overall record of all the teams that did not win their division. That team is called the "wildcard" team.