Funny Memory

I've been really struggling to think of a funny memory. Why is that? I know I've had some because I remember having big belly laughs, but I can't for some reason think of one in an actual situation ... I've had them while with family, friends and work colleagues, at home, at other peoples homes, at work and on nights out.

Does it really matter that I can't remember an actual specific time or is it more important that I know I've had some?