Good Riddles

 
Riddle #151 (medium)

Question: Travel a mile and I will change.
Travel a million and I will end as I started.

What am I?

Fun (medium)

Question: What key is playful?

Question: What melts in a freezer?

Question: I am almost nonexistent through sorrow, yet am frequent through happiness. I have no contact, yet I am contagious. What am I?

Riddle #618 (medium)

Question: You put me on a table and cut me, but you don't eat me.

What am I?