Me too, buying materia and leave it right there.

I also remember that demon-gate-pain-in-the-ass-boss. Didn't see that Bahamut materia (which is very useful in that fight) and tried to fight the gate just with normal attacks. I lost every time. I thought demon gate was some ultimate boss and didn't fight it and trained till my chars were lv. 65. Took me countless days to do so. Then i beated the gate and wondered why the bosses after that were so weak.