It depends on what type of flicking.
Although I can flick open most of my knives, I find flicking by wrist-snapping alone as more "showing off" than practical.
In addition, some knives are inherently more "flick-friendly" than others. For example, it is much more difficult to flick some lockbacks with heavy backsprings, than it is to flick a loose linerlock.
Therefore, if you can't duplicate that same action with different knives, and under varying conditions, it is more of a trick than a skill.
However, flicking by using the thumbstud is much more certain. That is, you nudge the blade with your thumb (or thumbnail) as you flick it. Let's call it a thumbstud-assisted flick. It is also safer since you aren't wailing on the knife and will therefore lessen the chance of the knife flying out of your hand.
Keep in mind that the shock that the knife endures with that snapping action may not be so good for the knife. Kind of like dry-firing a gun.
So, yes, I do snap open knives occasionally for fun. However, I keep it to a minimum.