I guess you have never been to Venice! Great offices, great food, beaches, way more cute girls, coffee shops (yes, even Blue Bottle and Philz, and tons of independent places). In fact, Abbot Kinney was literally named the coolest street in America by GQ!
Night life is also great. Main Street is fun, it starts in Venice and continues all the way down the beach into Santa Monica. Tons of bars and places to eat.
You're right, downtown sucks. You drove to the wrong place at midnight. That's why there are no impressive startups there and no one lives there. Traffic also sucks there in general, so you don't work downtown. I don't have to take any freeways to get around and actually spent more time in traffic in SF (driving from Palo Alto). It's in no shape or form a dense city, but there are more things to see as a result.
Pasadena is one of the worst areas in LA, if you ask me. It's hot, nowhere near the beach, and boring. So I'm not surprised you don't like LA if you think that's the best spot!