Forum:Bioware...Why so serious ?

( *** This might contain SPOILERS *** )

I'm a relative newcomer when it comes to Bioware games. I've only played the Dragon Age and Mass Effect series. What I don't understand is why Bioware can't work in a "Happy or Feel Good" ending.

I know that seems really petty considering how well made those games are and taking into account creative direction and desire on the parts of the writers but why do the main protagonists HAVE to always go M.I.A ( Warden / Hawke ) or be killed in action or be "Presumed Alive" ( Shepard in ME 3 ).

I can see why they might do this but on the other hand I can also see some people getting pissed do to all of the hard work and emotional investments he/she has made in their Wardens, Hawkes and Shepards only to see them eather go missing mysteriously or be killed in action when most if not all of the people your character traveled with is still alive and gets a feel good sendoff.

....Is this just a theme in Bioware games?