No, no, no, that is not bad karma. You have a legal right to take breaks and you can do whatever you want on those breaks. Do you need someone to give you permission to hit a thrift on your break? Okay, I hereby give you permission. Enjoy!

(The fact that you lie and tell your coworkers that you're going to the post office, though...hmmm, what's that all about? I hereby give you permission to not feel guilty or embarrassed about going to a thrift.

)