niggling

(verb) worry unnecessarily or excessively. Synonyms: fuss, niggle, fret. Examples: "Don't fuss too much over the grandchildren--they are quite big now."

(verb) argue over petty things. Synonyms: quibble, niggle, pettifog, bicker, squabble, brabble. Examples: "Let's not quibble over pennies."

(adj) (informal) small and of little importance. Synonyms: fiddling, footling, lilliputian, little, piddling, piffling, petty, picayune, trivial. Examples: "A fiddling sum of money." "A footling gesture." "Our worries are lilliputian compared with those of countries that are at war." "A little (or small) matter." "A dispute over niggling details." "Limited to petty enterprises." "Piffling efforts." "Giving a police officer a free meal may be against the law, but it seems to be a picayune infraction."