How does all the good things lead to the major bads?

Everyday we here about how the world is in wars and slowly fallin apart.... but then say you find something that seems good fair and the best of both worlds.... the love starting to fall into place gets hit by a wave of gossip and lies.... why can't people leave others be when the one wants nothing to do with the other.... then just as you feel nothing could ruin a moment the death of a friend causes a total shutdown of the love system and you don't know what to do to get the hurt off their minds.... so why do the good things always usually have to be followed by the majorly bad?