LONDON — When a coach as experienced and as successful as Louis van Gaal keeps having to listen to speculation that he is about to be fired, it is bound to get under his skin.
And when that coach hears — too often for it to be mere rumor — that his former protégé, José Mourinho, is waiting to replace him as Manchester United manager, is it any wonder that Mr. van Gaal seldom seems to be enjoying his work?
After one of the worst weeks of his career, the 64-year-old van Gaal came out smiling on Monday. In fact, he was smiling so much before, during and after United’s 3-0 win in the F.A. Cup at Shrewsbury Town that it began to look as if he has been taking drama lessons.
Nothing much else had changed. After Manchester’s shocking loss to the Danish club Midtjylland last…