scientists call this thing brain self-persuasion.
example:
you playing ttrr offline, plopped first worm and the next moment your 2nd turn started in which you made a successful run, and the next turn you failed. And you'll feel like you did alright because in offline fail cost you few loosed seconds, in fact the brain doesnt even pay attention at those
then you playing online, once you fail first worm you'll think to yourself how terrible you are currently in terms of the roping shape, because now you actually gotta wait like few mins till everyone else use their worms. thats more than enough to feel all the rage, and if you fail your 2nd worm your chances to perform rage quit rises in geometric progressions
there is some other factors as well, like being relaxed with makes controlling better as well as lack of nerves, and fingers sure warms faster since there is nobody except you in offline. all those factors on couple make such noticeble difference