Happens all the time to me. The problem comes from the fact that the games are too easy in general, so sometimes I'll decide to gimp myself in certain battles. Like, not using my strongest abilities (Overdrive, Limit Break) when they become available because the boss will die in one hit. From time to time my toying around gets me killed though. Most recently it happened against both Seymour and the Sanctuary Guardian on Mt. Gagazet in FFX. Only two Game Overs I've seen this playthrough.