If you just touch the case while the case is grounded it does the same thing as that picture :).

LOL please this thing can almost be called an old wives tale.

I been putting computers together on my CARPET FLOOR with socks on and have NEVER had issues

Nah, just grab your case to release any static charge and you're fine.

When I built a PC for the first time (it was my second ever x86 PC, having bought the first already assembled) I had one and I used it, now I'm more careless, I just take care to not wear any wool or synthetic clothes, I first assemble the PSU if it isn't already done, I keep it plugged so that it's grounded, and I touch often metallic parts of the case.

PS And I keep away my cats, particularly the black ones, that for some reasons buid up the most powerful electrostatic charges, and even if they didn't, they'd try anyway to steal screws, nuts and bolts).   

I should, but I don't have one.

No, but I do use motherboard anti static bags in clever ways depending on the situation, I know what would and wouldn't fuck up your parts from lots of experience lol.

No. But I do touch grounded metal sometimes. Or used to.

I use the wrist strap, largely out of habit from over a decade ago. My brother, on the other hand, is the complete opposite, and doesn't even worry about grounding himself. Even though the computers he builds are fine, I just can't shake the habit.

I just touch the case periodically.

1 build. Didn't use it. I just kept touching the back of the case frequently, used a large wooden table and the box of my motherboard for the test build. No carpet nearby the work area. I do get shocked by my car door every now and again so it was something that I thought about frequently.