3) Transporter Technology Fixing All The Things
All the messed up situations can be sorted out using the transporter. It was used as a plot device in many of the episodes. The real problem was when the actual advances made using it were forgotten by the time credits started rolling.
The episode “Unnatural Selection” in The Next Generation showed that Doctor Pulaski is infected with a disease that alters her DNA, speeding up her aging. When she is about to die of old age, Captain Picard realizes that they can cure her using The Transporter. They used a sample of her DNA, from before she was infected, and as a filter to fix her altered DNA.
I don’t know how, but it worked and turned her back to her normal self. This means that this rejuvenation technique of the Transporter is essentially Fountain of Youth. Using it you can just turn your looks as per your wish.