A slideshow about your recent holidays used to be a powerful threat against those of your guests, who were in no hurry to leave.
You gave the signal, they suddenly rememberered they were expected somewhere else.
Today, Gondorla Subliminal's slideshow is a free hypnosis session. An empty mind guarantees bliss.
For optimal results : on the GS screen above, shift to full screen mode.
Plunge the room in which you are into total darkness.
Or as a last resort, change slides manually. This may bring tendinitis since you will obsessively click to make it work.
If the slideshow is not displayed properly, it is probably your fault. Too bad.
You will get over it, but you will have to use your own judgement.
All in all, you could use preliminary exercices.
Or you just move on to the analogies
If you have not already done so, read those users' testimonials.