For me, it depends on the game.

If by completing the game, we're talking about doing all the sidequests, defeating the optional bosses and all that other relatively accessible stuff - I've done everything there is to do in FFVII-FFIX and FFXII (Excalibur II only with FMV skipping though.. actually, I didn't know you could do it on PAL without resorting to it). The only thing holding me back from knocking over FFX is lightning dodging. I've also only beaten Penance with Yojimbo, so I probably shouldn't get the brownie points for that either. With all the older FFs, I'm happy to just clock the story and do a few sidequests to get the better weapons.

If we're talking maxxing out stats, getting 99 of every item... Nah.