One Landlord had a habit of every day throwing thousands of rupees from his balcony. Poor people would gather down the road to pick them up. But He noticed one thing that nobody would see up and thank him. so He got very angry and wanted to test them. On next day he threw stones instead of rupees. As they got hit, everyone started cursing the landlord.
Similar is the situation of this world where Lord provides us for our all daily necessities of oxygen, water, food etc. but nobody bothers to thanks Him but when because of their own misdeeds when calamity comes they curse the Lord.