aggravation, aggro(British), annoyance, bother, botheration, bugbear, exasperation, frustration, hair shirt, hassle, headache, inconvenience, irk, irritant, nuisance, peeve, pest, rub, ruffle, trial, vexation

discomfort, fleabite, pinprickaffront, insult, offense(or offence)upset, worryaffliction, albatross, burden, cross, curse, menace, millstone, plague, soreanxiety, plight, predicament, tribulation, troublehang-up, pet peeve, problemannoyer, disturber, harasser, mischief, offenderpandora's box