When the game was more active, at least on flash you could tell who the teammates you were with if they were gonna be selfish or helpful medics, and there was quite the variety. Some people are just careless of their 'teammates' and only think for them selves, or rush ruining the fun for others, you'll find that in any game. 

LMS use to be more fair, same with apoc, the zombs were given a massive buff making them unfair at very early stages and LMS now has a wave mechanic to it (it use to be an endless thing), even for level 100 vs games. It use to be in Virus Samples and LMS that if you could tank, you could tank, and if you could tank and heal, you had the advantage until the dms came along.

Those players who still unbelievably waste their lives with the game, i see them everytime when i log on every now and again, they just grief those who aren't as tryhardy with a game that relies on having a better gaming PC/mobile. 

In LMS, it is normal to be selfish. As the goal is simply, let every fellow SAS die and earn score.

Apoc, now that's when teamwork is needed.