Putting all of your cards in one wallet
Unfortunately, robbery is on the rise. If you're like most people, you carry all of your credit cards and IDs in your wallet. While convenient, this makes having your wallet stolen that much worse. When you cancel all of your credit cards, you'll quickly find yourself completely disconnected and without resources. Even the simplest things like buying groceries and gas become difficult. Your apps and internet subscriptions will stop working too; that means no Amazon, no Netflix, and no GrubHub.
While I hate using cash, it's important to keep some on hand as a contingency. It also doesn't hurt to have a spare credit card at home just in case. Store these in separate places to improve your chances of having at least some resources available if you end up in a situation like this. Hopefully, you won't need them.