Lycanorukke
SOC-13
Actions should have consequences. Levels of accomplishment should have consequences. What happens in a side quest should effect the main quest.
I agree with that to a point. Excessive side quests disconnected from the rest of the world is annoying (as in almost all Bethesda games), however if everything is linked into the main quest, it can rapidly become painfully contrived and predictable.
Saving Granny's cat from a tree should just be saving granny's cat from a tree, and not actually foiling a secret plot by evil grandmothers to control the distribution of cat litter and thus the kingdoms economy.
With a good GM in PnP games, if a side quest becomes interesting you can always retroactively tie it back into affecting the main quest or even become its own main quest. Conversely if it flops and bores players to tears you scrub it as a 'one off' which has no lasting effect. A good GM who can adapt will always be superior to a programmed response tree on a computer game.
As for vid game examples - I would go Witcher 3. While there are side quests which are unrelated to the main quest/s, there are others which _do_ affect the main plot and can come back to bite you hours of game time later. The catch is though, they are not advertised as 'mission affecting' so you have to think about it. Nor are the choices 'Press X to be a saint' or 'Press Y to be a demon'.