I think I've discovered a handy way of summing-up how I think about designing user interfaces: No Lorem Ipsum!
A Symptom of a Bigger Problem: Lazy Product Design
Lorem Ipsum isn't always bad. It's often useful in "marketing pages" - places where you want to indicate there will be a few paragraphs of text here, a sentence or two there, etc. But when designing interfaces? No way. Use Real Data. Text that represents, you know, what the user might actually see.
Designing and building great software is hard. You've got to put yourself in the shoes of the end user, try to understand their needs and motivations, and try to create a tool that's really useful (and hopefully fun and interesting too). You've got to sweat the small stuff. Every screen. Every permutation of every screen. Every label, every text box, every error message. It's the accumulation of thousands of design decisions that makes something great.
Using "Lorem Ipsum" or "Menu Item 1" or "Product 1" (or whatever) makes it harder to design great software. What happens when "Product 1" becomes "How to Be Funny: The One and Only Practical Guide for Every Occasion, Situation, and Disaster (no kidding)"? Find out early so you can design accordingly.