Be honest with yourself - if you're not, there's only one person you are fooling.
When we say we have been "good" and deseve a loss, can we honestly say we have been good? Have we weighed and measured our A's and B's, counted all our syns and stuck to plan 100%? If so then we can be disappointed but it's not always true, we can't honestly say we have been "good" - slimmer's amnesia always kicks in.
Always be honest is my tip for non-sw things too :-)
That and live each day like it's your last, I lost my best friend a few years ago and I miss her terribly, I'd have loved to have done so much more with her, now I try not to let any opportunity pass me by.