Friends was absolutely brilliant in the first two series, maybe three, and then it turned into a terrible parody of itself. Compare the Monica of the first series with that of the later ones, they aren't the same character. I still have issues with the affect it had on the way people speak, like, you know, err effecting this stupid way of talking, I mean, huh, could it be any more annoying? Rachel was the only reason for ever watching this in the latter years.
The only show I've ever felt really attached to, and mourned the end of, was Lost. It was incredible, the way that first episode hooked me. I imported the US DVD set as soon as I could and finished it within days. I used to think up excuses to finish work early every week to get home early and start torrenting the latest episode, wait the three hours or more for it to download, watch it transfixed and then spend the rest of the night reading theories and looking at sites the poured over every little detail of every episode. Summers were hard, I'm sure I had withdrawal symptoms. I rewatched the first series numerous times. When I was travelling across America in 2008 I tried to make sure that I stayed in a hotel and not a hostel for when it was aired, so that I could watch the new episode in peace. When that wasn't an option I made sure to book the tv room days in advance, or befriend someone with a laptop and download it. I was obsessed. It ended badly, of course, but it's still the greatest series I've ever seen. I think I'm getting the blu-rays for christmas and I'm going to work my way through the whole thing again - and I can't wait!