looking in the dictionary...for the word opportunist which i wish to feature today as a friend has regrettably, shamefully and reprehensibly come to define the concept so well, that, cliché or not, i was convinced i'd find his photograph or a likeness of him along with text... remember the song at both beginning and end of almodovar's splendid women on the verge of a nervous breakdown? «¡lo tuyo es puro teatro..!»
opportunist: noun. a person who takes advantage of opportunities as and when they arise, regardless of planning or principle. an organism that takes advantage of temporary or local conditions; a person who takes immediate advantage, often unethically, of any circumstance of possible benefit.
realistic definitions giving it a somewhat positive twist, defines him as a person who starts taking bathif he accidentally falls into a river... that to me defines someone resourceful or rather, an optimist because the opportunist really won't do somehting unless there was something to be done at the expense of someone or something else. related word, north america: i>carpetbagger: the unscrupulous opportunist.
sources: the compact oxford english dictionary, cornell university and princeton, as well as the realistic definitions page.