A union is a organized group of workers who come together to make decisions about conditions of their work. they have the impact to change:
Wages
workplace hours
benefits
Health and safety
Contracts
5 Negative things:
Being told what you can and cannot do
If the union goes on strike you have no choice but to as well
Going on strike puts a financial burden on your family
Being threatened if you are a hard worker and make others look bad
Having to sit around if there is no work