The problem:
Say minimum wage is $8 an hour, but you need $8.50 to live comfortably.
You gather a plethora of fast food workers and start a strike to bring minimum wage up to $8.50 so you can provide enough to live comfortably.
The strike was a success! You and your friends have managed to change the law to fit your needs! No longer do you need to worry about being able to put food on the table or pay your rent. You have just the right amount of money to do so.
However, to combat this loss in profit, many companies begin to raise their prices by a few cents, practically unnoticeable. This "unnoticeable" price difference adds up, and suddenly...
You need $9 an hour to live comfortably.