1 He who gives no thought to far-flung problems soon finds suffering nearby (idiom, from Analects).
2 Smug concentration on the here and now will lead to future sorrow.
千虑一失
qiān lu:4 yī shī
1 reflect a thousand times and you can still make a mistake (idiom); to err is human
千虑一得
qiān lu:4 yī dé
1 a thousand tries leads to one success (idiom, humble expr.); Even without any notable ability on my part, I may still get it right sometimes by good luck.
智者千虑，必有一失
zhì zhě qiān lu:4 , bì yǒu yī shī
1 lit. a wise person reflecting a thousand times can still make a mistake (idiom); fig. nobody is infallible
朝不虑夕
zhāo bù lu:4 xī
1 at dawn, not sure of lasting to evening (idiom); precarious state
2 imminent crisis
3 living from hand to mouth
杞天之虑
Qǐ tiān zhī lu:4
1 man of Qǐ fears the sky falling (idiom); groundless fears
殚精极虑
dān jīng jí lu:4
1 to exhaust one's thoughts and ingenuity (idiom); to think sth through thoroughly
2 to rack one's brains
3 to leave no stone unturned
殚精竭虑
dān jīng jié lu:4
1 to exhaust one's thoughts and ingenuity (idiom); to think sth through thoroughly