You don't feel static until 8000 volts. Your computer runs on microvolts. So all it takes is a few volts of static across a mother board and you can destroy small components and not know. The device will still run but will run intermittant and may fail in 6 months.
Build your own computer and never touch anything. I use rubber latex gloves, install your power supply and plug it in first for ground.
Never let anyone else build your computer.... 
I think latex may allow static buildup as well, ever rub a balloon on your clothing and have it stick to walls? If in doubt, wear a wrist strap grounded to the case or ground yourself and work one handed, better to just buy a wrist strap. If you will do a lot of handling, a special mat to stand on as well as to put on the work bench is a good idea. Many work shoes you buy have static resistant soles.
If you see the ESD symbol on the packaging, take the necessary precautions. You can't harm a component from being too careful with ESD.
As far as packaging, here is a partial rundown.
Some bags such as pink poly bags do not generate static but they also do not protect against it.
Other packaging such as metallic coated bags will protect from static AND not generate it.
