眼高手低

- have grandiose aims but puny abilities; be fastidious but incompetent; flit from one thing to another; great ambition but little talent; have high aim but no real ability; have high ambition but no real ability; have sharp eyes in criticizing others but clumsy hands in doing things oneself; high in aim but low-rate in execution; like to criticize but do not work oneself; One's ability doesn't match one's wishes [high goal].