Good Riddles

Question: You walk down a path through the woods everyday. You always walk by one particular large rotting log which weighs over a ton. The next day you notice that there is another large log underneath the familiar one that you've never seen before. How did it get there?

Question: A man looks out to a boat full of people But there's not a single person on board. How is this possible?

Question: How is 2+2 four, 3+3 eight, and 7+7 triangle?

Question: Sometimes, I leave you with “mixed” feelings. More times than not, I teach you a lesson. I give what I didn’t create. What am I?

Question: You can rest on my pad without touching the keys.
I will sing all month long as long as you pay your fees.

What am I?