Maybe it's one of those things where a good union is good and a bad union is terrible. It's easy to say how good a union could be, but will it actually be that

Maybe it's one of those things where a good union is good and a bad union is terrible. It's easy to say how good a union could be, but will it actually be that good? What kinds of things can go wrong? What weird laws are in place and how could that complicate things? The bottom line is that if I am happy already, a union is more risk than reward.