wow.. the hate.. a good place to start would be tonmo.com those guys are where its at.
i will tell you without a doubt keeping at an octopus is one of the most rewarding things that you can keep. that being said. they do require very special daily care.
they are messy so you need super great filtration and be on top of your water changes.
you'll have to cordon off ever. single. hole. including filtration. they will absolutely pull off a filter and stick that tentacle right into an impeller if you do that wrong.
you will never be able to aquascape because they make all decisions regarding their habitat. no large rocks that can topple, because it'll either go thru the glass or possibly fall on the octopus.
toys. they need daily enrichment. playing with it is fine once you have established that relationship. food in a jar is not enough, they like to mix it up. as an example one of mine's favorite thing in the whole world was the large plastic end to a siphon that floated, she would stick it anywhere, put rocks in it to keep it down. sit on top and pull the rocks out so it would float up. put it in the flow of the return and ride it around. crazy stuff.
you have to know what species youre getting. pygmy's while small, liver shorter lives. bigger ones live longer, but require larger habitats. once a female lays eggs, she will brood them until she slowly dies. its the most depressing thing ever. males, depending on the species can live longer especially those that never mate.
the statement "you will never be able to go on vacation" is 1000% correct. i didnt even like to leave mine over night.
most are nocturnal, but can make the switch to crepuscular in captivity, ive heard of some that go diurnal but ive never seen it.
no lights. you can have some week ones on during day, and red on at night but remember what youre keeping here is an animal that likes to hide. let it. if it doesn't like the lights it WILL find a way to take them out.
they are smart as all fuck. they will learn your habits and learn to love you if you love it. conversely, if you get one and dont do it right it will either die, or not give two shits about you and you'll end up with an animal that hides from you... may not eat and can very possibly be a total dick while your trying to clean the aquarium.
if youre not already pretty damn good at keeping marine stuff i'd stay away. do a shit load of research before you even try.
tl;dr: no. read it.