Ask people at Manchester City why Roberto Mancini was sacked four-and-half years ago and they will provide half a dozen reasons. Ask Mancini the same question and he will give you one: Robin van Persie.
In early 2012, Mancini thought he was favourite to sign Van Persie for City from Arsenal. Manager of a team that would win its first Premier League title later that season, he had met the Dutch forward and Van Persie had even looked at a house.
In the end, Van Persie moved in to that house but only after performing a neat volte face and signing for Manchester United.