There are medical conditions that can cause a small amount of alcohol to be in the blood and there's always the morning-after problem. There are practical reasons for allowing a small amount.
Drugs, however, are a different matter.
I've just watched the MOTD highlights and what stands out to me is that if Pellè just lifts that chance over the keeper instead of lashing the ball over the bar then it would have changed the whole complexion of the evening. We're not off where we'd like to be.
Are you thinking of a blown head gasket?
Normally any coolant leak is fairly obvious because of the colour but if there are no obvious signs then it must be going somewhere.
Quite right, I've just looked at it again myself. Jose plants his left foot and then his right leg swings round and catches Aguero on the ankle. Aguero has seen it coming and is already putting on his agonised expression before the contact is made. The tell-tale sign that he is making the most of it is that he makes no attempt to get over the incoming challenge but actually swallow-dives over the incoming leg and throws both his arms back. Having said that it was a 'trip or attempt to trip' and should have been a penalty but Aguero's theatrics were enough to persuade the ref otherwise.
There was a seller in Britannia Road after the game with a big pile of them still unsold. The only thing you could do with them was buy two and cut them in halves.
It wouldn't have been a red as there were others covering and Agüero wasn't running towards goal but even so it wouldn't have been pretty. Once they scored it was always going to be a struggle.