highs:

-8 or more titans/sabres against my eagle.
-4 titans against my dromedary. i survived the first wave. blown to bits in the second.
-having a dogfight in a minefield or gas explosive field.(lvl 10 shield of course)
-the sp story.
-seeing juni walks.
-multiplayer and helping noobs.

lows:
-the long boring traveltime.
-you dont get the chance to meet up the guys(juni and co) after the story ends.
-couldnt kill any battleships on mp.
-couldnt own a planet/battleship/etc.

To me, FL has a low for each of its highs, so that they largely cancel out and leave you with basically nothing. For instance:

High: Constant, intense, fun space combat. Low: Strong incentive to avoid the same unless somebody is paying you for it.

High: Dynamic universe with scads of factions. Low: Inability to play in it during SP game due to the storyline leading you by the hand and choosing all your friends and enemies.

High: Interesting, engrossing SP storyline with a variety of mission types. Low: Keeps you from doing your own thing until it's over, and when it's over you've already seen and done pretty much all there is to do, so why bother continuing?

-Bullethead

In wine there is wisdom, in beer there is strength, in water there is bacteria