I asked my Spanish godmother how do differentiate between "You make interesting things" and "You make things interesting. Here's the response:
You make interesting things --> Usted hace cosas interesante.
You make things interesting --> Usted hace las cosas tan interesante.
Hope this helps.
John & gabriel
"Cosa" is 'thing'.
"Algo" is 'something'.
'Interesting' is describing 'thing' and 'thing' is general, not specific (no article). So it's 'interesting things'.
For the sentence to be as others have tried to translate: 'you make things interesting', 'things' would need an article in front of it.
"Tu haces las cosas interesantes" is 'you make things interesting'.