The first, given to me when I asked on here, was "Always keep your mouth shut when jumping into water".
The second, from experience trying to fend off the flak: Do not spend nearly £100 on matching boots, numnah, XC shirt and silk for your child's first attempt at XC training. Especially not if you can't then find the venue for two hours and then threaten to sue the organisers for the return of the money you have spent on the now-redundant gear.