I am going to go out on a limb and guess that her statement was mostly a joke. LA has high rises, they are just less common. The average apartment building is between 2 and 5 stories. It is the land of earthquakes after all.
As a recent transplant from LA to the East coast (new jersey but I have gotten the chance to spend time in Manhattan and the Bronx) some things that havent been mentioned.
It is not a car culture like you are used to. Things that are really close together take forever to get to by car because things weren’t planned with cars in mind. That said stuff is really close together. Like Midtown Manhattan to downtown Manhattan is smaller than Santa Monica but it has dozens of seperate little sub neighborhoods.
The pizza is great and crazy cheap, the Mexican food is not bad but …not right. It’s either too authenticly homeland or way too gringo (and too expensive) and the Chinese food is very good but different.
People tailgate like it is not unusual to leave less than a car length between you and the car in front of you and the first person in the left turn lane almost always jumps the light rather than waiting for a traffic break.
People are very friendly. Not southern hospitality friendly, but not isolated and stand offish like in LA. If you go into a shop the shopkeeper and even other customers are likely to strike up conversations with you about things that have nothing to do with shopping in that store. It’s weird. I like it, but its weird.
I’ll add more as I think of it.