cheerful (
http://definr.com/cheerful)
adj 1: being full of or promoting cheer; having or showing good
spirits; "her cheerful nature"; "a cheerful greeting";
"a cheerful room"; "as cheerful as anyone confined to
a hospital bed could be" [ant:
cheerless]
2: pleasantly (even unrealistically) optimistic [syn:
pollyannaish,
upbeat]