I stopped watching it at about episode 7 of series 1. But I read a while ago that the writers admitted in an interview that they are just making it up as they go along - there is no big plan of what it all means or how it's going to end.
i have seen both series and thoroughly enjoyed them both.yes,some episodes are dull but in the big scheme of things even the poorer episodes have something to contribute.
i have no problem sticking with it as half the fun is trying to 2nd guess what is going on.
It all comes down to the sandwich filling in a lunchbox that the lead characters brother ate when in school at the baseball match that they lost. Flashbacks throughout the next 10 years will bring you to this marvellous revelation.
apparently there will be around four series then a feature length film which reveals all the answers, so you will probably just have to wait until then like the rest of us : (