Possibly Negative Trends are Tattoos and Piercings. They might end up negative because they are permanent.
Tattoo
Why you should have one:
-Tribal
-Expression
-Remembrance/Memory
-Tribute to something/someone
-Trendy
Why you shouldn't get one:
-Lables
-Hard to remove
-Cant give blood
-Harder to get a job
-Infections
-Mistakes and Misspellings,
-Will change as you age (fading, stretching, ect)
Piercing
Why you should have one:
-Tribal
-Beauty
-Cultures
-Expression
Why you shouldn't have one:
-People think it's strange
-It can easily go wrong
-Infections
- Hard to remove
-Harder to get a job