That's because you're assuming everything is logical except the person complaining. I've seen this before from the perspective of latency and you often don't even see them spamming health potion until a critical point where you're going to be in trouble. For starters, from the user's perspective, the animation to draw the Medkit doesn't take long and you can stab the first one in before it finishes completely. From then on, subsequent Medkits can be chained fairly easily and frequently, if necessary. As mentioned, the kit restores full health; though the effect may have a time limit, with the speed it works, it will negate all subsequent damage received until full health is achieved once. By the time the shooter will have realized that their target has been alive for far too long on their client, the shooter will probably need to long reload. It's more like spamming kits is allowing them to get to cover under fairly accurate fire, or allowing them to perform extensive maneuvers when not under cover against an otherwise unrelenting source of enemy fire. (Combining this with a Resist Shield increases the time alive of the user immensely, almost to the point where he could run towards his shooter and not die and still have his Shield when he chooses to re-engage.) I need not remind what "getting behind cover" means in a game like this. That's almost a complete reset button for the advantage one gets out of clientside latency.