i've learnt that when you hear c02 escaping from the post on your keg of Porter that has just been force carbed that it isn't a good idea to just give it a little push so it re-seats itself nicely. Especially when you are using the in-laws brand new apartment for brewing in whilst they are overseas.
End result was Porter all over me, all over the ceiling, all over the walls, all over their upholstered dining chairs. Managed to clean most of it up, but even after bringing in professionals to clean the upholstery you can still see the stains.