Apparently, because of how much motion an octupus' tentacles have, they aren't fully in control of them, so they move almost with a mind of their own.
Also, because of how sensitive they are, an octopus can't put information picked up by the tentacles together. For example, a human could close their eyes, and with one hand feel bark, and the other hand a load of pines, and conclude that they're touching a pine tree. An octopus would feel the bark, and feel the pines, and if it were capable of thought, think, 'Whatever this tentacle is touching has bark, and whatever this tentacle is touching has pines.' They're not spacially aware of the tentacles either, so they can't relate the position of the tentacles to each other. the tentacles might touch each other, and it might think, 'Wtf, this tentacle feels a tentacle, somewhere out there is an octopus!' haha
Lol, I seem to know a fair bit about the octopus