yeah but it makes you look pro if you put one on in front of a customer.
Depends on the customer -- if he/she is a techie too, then they may even take you *less* seriously if they see you use one.
anyway, I used to live in a place high up with low humidity, with terrible static electricity issues. (e.g. get zapped all day long each time you touch a door handle, etc.) Even there, just touching the chassis of a computer first is enough to get rid of the charge.
Never used one, never blown anything up.
Famous last words? :-)
many years ago before Ethernet was affordable, there were some popular programs that could transfer data over either serial or parallel cable between PC's. I remember someone about to plug one of those cables in between two live PC's.
"you really should turn them off first"
"nah, I've done this a million times, and never fried any~snap-crackle-pop... and best of all was the little puff of smoke that slowly floated upwards. If I had seen it on film instead, I'd have sworn that it was added later as a special effect.