Avantages
You see a lot of familiar faces, including store regulars and people you might know from elsewhere. Some of the regulars are shoplifters (who shoplift regularly enough that you'll know them), but the majority are retired folks or ebay resellers who buy items to flip online. Talking to these people keeps you sane and gives you a chance to smile and make connections. If you spend time sorting in the back or on the floor, you see a lot of interesting stuff, and if it's still out there after the mandatory wait period, you can buy it for yourself. Most of the stores have free coffee and they didn't have a problem with the employees drinking it.
Inconvénients
Goodwill is run like a business, but is masquerading as a charity complete with non-profit status and everything. They DO have some good programs, but the thrift store part of it is separate and is run in a typical cutthroat retail fashion in order to fund the programs. Don't expect the "goodwill" to reach your pocket or your working environment. Having said that, your experience may come down to the people, I had a boss who was a narcissistic gaslighter. Other employees were totally neutral and unmemorable, and one or two who were decent people who I would be thrilled to see again. Goodwill throws out TONS of good stuff. Remember, the ultimate goal is to make money. The other half of Goodwill will use that to provide some programs, but if we have to chuck 100 lbs of perfectly usable good stuff to make way for some great stuff that we can sell for more, it's time to fire up the trash compactor and crush some stuff!