This one is another classic. I find the incongruity of the comparison the most appealing.
When a day that you happen to know is Wednesday starts off by sounding like Sunday, there is something seriously wrong somewhere.
The Day of the Triffids by John Wyndham
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When Bill Masen wakes up blindfolded in hospital, there is a bitter irony in his situation. Carefully removing his bandages, he realises that he is the only person who can see: everyone else, doctors and patients alike, have been blinded by a meteor shower. Now, with civilization in chaos, the triffids – huge, venomous, large-rooted plants able to 'walk', feeding on human flesh – can have their day.