Like Moot said, it's all relative. If you have a minimum wage job, then a $1000 pizza is definitely out of your price range. If you make $1000 an hour, a $1000 pizza is something you won't blink at. I know people who think $100 for a pair of shoes is ridiculous, but I also have a friend who routinely drops $1000 or more on a pair of designer shoes, that she might wear once or twice. But that $1000 is relative to her income. She can buy 5 or 6 pair at a time and not think twice about it.
As for caviar and lobster, you can go into some restaurants and buy lobster and caviar and it will cost you $1000, and it's served on a plate. At least with the pizza you get some bread. There are certain types of caviar that will cost you well over $1000 an ounce. I have a 250ml (about 1 cup) of Pedroni balsamic vinegar that's 75 years old. I got it more than 10 years ago and paid a little more than $500 for it. It comes with a hand-blown eye dropper for dispensing it. High dollar, but a drop goes a long way. I'm down to about 6 ounces now. I've paid $25 an ounce for white truffles. You want a good steak, have an Angus NY strip. You want a steak experience, try Kobe Beef. Want to jazz up a $5 Foot Long, add some American White Sturgeon Osetra caviar to the mix. It's about $50 an ounce, but one ounce will do 4 or 5 sandwiches.
When it comes to food, always start with the best ingredients, and then don't screw it up. If you can do that, it becomes a culinary experience instead of merely a meal. If you can afford it, you'll never be disappointed with the best, when it comes to food, or most anything else.