Hint: Another word for 'happy'
The answer to this puzzle is:
1. ECSTATIC
2. MERRY
3. RADIANT
4. BLISSFUL
5. CONTENT
6. DELIGHTED
7. THRILLED
8. JOYOUS
9. EUPHORIC
10. GLEEFUL
11. JOLLY
2. MERRY
3. RADIANT
4. BLISSFUL
5. CONTENT
6. DELIGHTED
7. THRILLED
8. JOYOUS
9. EUPHORIC
10. GLEEFUL
11. JOLLY