Commie, daigong, and everybody else who's spokent of feeling guilty: I think it's something which comes up frequently when you're dealing with the emotional effects of the death of someone close to you. You get the questions: Could I have done more? What if...? Why was it him instead of me? Do I deserve to be alive now?
And you get the guilt over being happy, or enjoying life: How dare I feel happy when he's dead? How dare I dishonor him by laughing? If I relax and go on with my life, won't I be forgetting him?
That's not easy stuff to deal with. In people with severe post-traumatic stress, those questions, and the emotions associated with them, can be almost overwhelming, and even life-threatening. But even if you don't have full-blown post-traumatic stress, dealing with those feelings can be very difficult and painful.
The bottom line is that it's not only OK to live your life and enjoy living -- it's necessary. We mourn the dead and treat them with love, with honor, and with respect, but we cannot let death invade life and take it over. It's as important to live, and to enjoy life, as it is to mourn the dead; I think that in many ways, we can't really honor the dead fully unless we
do give ourselves over fully to life.
This past weekend, I went to a memorial service for my uncle, and for one of his late wife's cousins. They were both quite old when they died, but they'd lived large, full lives, and up until the end, they were both very much a part of the lives of those around them. They were also both veterans of WWII, and the ceremony included military honors -- a National Guard color guard, and a 21-gun salute by the local VFW.
At one point, just before the ceremony, I looked up, and the two (young) National Guardsmen were flirting with the (also young) female VFW commander.

I smiled when I saw that, because it seemed so right -- and I knew that my uncle and his wife's cousin would have both smiled, as well. And I think that the rest of us who noticed it felt the same way.
We honor the dead by living life to the fullest -- so when you laugh, laugh like Jab would have laughed, and he's there with you.