The third trap sneaks up after you've bought one thing successfully. You think, 'Oh, this brand ships well, I'll get the glass tumbler too.' But here's the thing: packaging can vary by product. A shirt might come in a poly mailer, while a glass item needs a box. Don't assume—check the product page or ask.

Another confidence trap is ignoring the small stuff. You might buy a bag of beans and a mug, and the beans arrive with a crushed bag because they were tossed in with the heavier item. That's a packaging design flaw. Look for brands that separate items or use dividers.