because you are jolly
happy
happy chimp
Because he is happy
A happy lion is one that has had a kill.
To explain the joke "what do you call a happy frog, answer hoppy" you have to understand puns. Hoppy is enough like happy that it can be substituted.
salad
Khoshi
A very good friend
You probably should not call to wish him happy birthday because you told him not to call you. If you do call, he may start calling you again.
You shouldn't call him to wish him a happy birthday since you told him not to call. If you do call, it may give him false hope that there is still a chance for the both of you, and he will continue to call you.
Happy
From 'Agamemnon' by Aischylos.