Some players just click when they are part of a certain pairing or team set up.
Luiz had spent a lot of time with us and never really shone (a worldy against Sheff Wed aside) It was really only the season he formed a partnership with Kamara and had Tielemans breathing down his neck did he really come to prominence.
And then when offered a nice contract, on the back of that single season, decided not to sign it.
Lets not think we lost a McGinn or a Mings or a Konsa - players that have done it regulary over seasons.