Okay would be dull. It's like dying without leaving any mark in this world. On the other hand, being happy for a short time (by the way happiness is never constant) will give you something to hold on to and to work on/for.
I'd definitely be OK.
I'd settle for ok. Happy period would feel shorter sooner than it really was and the rest would look very bleak in comparison.
Experience has shown me that making it last longer is better for for anything