As someone with SA, my confidence is heavily based on how often people like me and include me in their plans, so when they don’t, I clutch onto all my insecurities and together we go down the rabbit hole and jump to the worst conclusion.
The less you’re invited, the less confident you feel when you do get invited — it's a self-destructive cycle of social isolation.
If you’re lucky enough not to suffer from SA, I only ask one thing: always extend the invitation. Even if you know for sure someone can’t make it or won’t be interested.