To stir up trouble or worry unnecessarily when there is no actual problem; to make problems for oneself out of nothing.
小明最近总是疑神疑鬼，担心作业没写好，老师会批评。真是天下本无事，庸人自召之
Xiao Ming has been overly suspicious and worried lately, fearing his homework isn't good enough and the teacher will criticize him. It truly exemplifies 'there was originally no trouble, but mediocre people create it for themselves'.
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