Stress
There's no time for stress when you need to find time to put the thumbprints in 600 jam thumbprint cookies, ice the tops of 250 cinnamon rolls, and get sixty trays of cookies into the oven—all in the next thirty minutes before the morning rush hits.
The exterior of a bakery might be quiet and picturesque. Stepping into the back room of a bakery, though, is a little like stepping into a stressful pit of hellfire. Sweaty, exhausted people shouting. Flour dust everywhere. A hot, noisy furnace. It's not a weekend getaway to the wine country, that's for sure.
But as a baker who has other customers and other bakers depending on you, you can't stress. You must stay calm, cool, collected. You can break down after your shift is over.