Dave Perell, in his weekly Monday Musings email, made a smart observation.

Whenever I’m in a city and I need to use the bathroom, I walk into a fancy hotel.

Fancy hotels always have nice bathrooms. And if you’re dressed well and walk confidently, you won’t be hassled for using the bathroom.

The world is becoming more casual. But if you dress too casually, it looks sloppy and careless.

When you want to cultivate serendipity, stick to the “Hotel Bathroom” dress code. Always dress well enough to walk into a bathroom at a hotel you’re not staying at and get away with it.

If you remember the “Hotel Bathroom Principle” you’ll always look sharp enough to capitalize on a serendipitous encounter.

This is good advice.