Gisele Bündchen's Travel Gear Included the Only Shoe I Wear for 10Hour Days

Before I tell you what it was, realise that this "mistake" is applicable to everyday life

not only when traveling through the airport

 I've only ever made one major travel mistake in my life

and I've never, ever made it again. So pay attention. 

I bought a brand-new pair of clunky, heavy sandals one summer while visiting Germany.

the flight rather than risk incurring overweight baggage fees that I flatly refuse to pay

 I hadn't even begun to walk when they began to grind on my heels

They seemed comfortable and stylish at the same time! a win-win situation.