Hal Jordan has the universe's coolest weapon and no idea what to do with it.
Hal Jordan got his powers the American way: somebody handed them to him.
A dying alien name "Abin Sur" (pronounced, "for-gett-ible plot dee-vice") crash lands on Earth and asks his ring to find an honest man to wear it once he's dead. Turns out he should have asked for someone with an imagination too. Hal Jordan is immediately transported/teleported/whisked away/zoomed over/shot out of a cannon (depending on which version you read or watch) to the crash site.
Hal accepts the ring and becomes one of the universe's most powerful beings!
If we could create hard-light constructs of anything we wanted ... we think most of them would look like this...
We would spend all day in our rooms with the green versions of whatever or whoever we wanted.
And...that's about it. No superheroics. No work. No school. This would pretty much take up all of our time.
With DC Comics needing a big crossover to coincide with the Death & Return of Superman from 1993-1994, they decided to make Hal Jordan go batshit crazy and try to take over the universe. One of the returning Supermen and the Cyborg Superman helped push Hal over the edge. He and a yellow-skinned villain named Mongul destroyed Hal's home, Coast City.
Hal looked at his ring and decided he should just re-create the entire city from his mind. Makes sense...if you've gone completely insane. He figured he needed more power to do it, though, and flew to Oa to obtain the source of his ring's power, the great big Power Battery guarded by a billion other Green Lanterns. Hal killed a few, chopped off limb's of others and absorbed the battery's power to become "Parallax".
Hal could have avoided pretty much every misadventure from the start. The key is to know who is going to turn on him in the end. See, several of his worst enemies started as his friends. He should have seen it coming, really. The trend seems to be giant heads and ugly mustaches ...
"Take that, Coast City!"
If only Hal had noticed his buddy Sinestro twirling his mustache and chuckling every time he saw a railroad track.