It feels like people really don't know how to play from behind

Like they REALLY don't know how to play from behind

• Laners who continue to build full damage into a losing lane, running straight to lane to get one cs, poked/traded to a pulp, and then dived under tower if they haven't already died.
• Carries that refuse to build Statikk Shiv or Luden's Echo or any other items that can help their champion's natural waveclear, meaning that if they fall behind and are undeniably behind the enemy carry in raw combat stats, they have little to no waveclear to defend our now losing sieges.
• Fighters and some tanks that are in the wrong place during sieges. Actually, I take it back, nobody knows where they are supposed to be during a siege. The carries who aren't building enough waveclear are too far back to defend the tower while it gets chipped away. The fighters who can't defend sieges for crap are placing themselves in front the turrets hoping to catch the minion waves, basically painting giant target signs on their faces yelling "Hey, poke me for free!". I can't decide what's worse; when a team queues a teamcomp that can't siege but tries to siege anyway, or when a team actually has a decent siege comp but still loses a defensive siege anyway!
• Everybody reacts. Nobody knows how to initiate action or plan ahead. I've honestly been abusing this strategy far too much personally, and it's a terrible strategy so I can't believe it's actually working on people. Build waveclear, build movement speed, shove one lane, and the moment you see an enemy coming near you, run off to another lane and shove that lane. Is the enemy team gonna 5v4 my teammates knowing I'm being dumb? Hell, even 5v5 us because I'm not building for combat anyways? Maybe get Dragon or Baron while I'm dicking off on the opposite side of the map? No, I'll have people chasing me around while I run much faster than they do and clear waves more efficiently then they can.

What happened to the days when it was common sense to build SOME defense if you're losing lane. To sit under tower or even just leave lane and roam somewhere else to be useful? And not even waveclear, why does it feel like people are still too anal about their cookie cutter builds right now, during the preseason when everything is in flux anyway cough Executioner's Calling? Why does nobody seem to know their place during a siege. Why are people still reacting poorly to the stupidest splitpushing strategies when splitpushing is so weak right now?

I'm 100% convinced that the only reason why games are decided so early is because nobody knows what to do after that first misplay or loss and just watch the snowball form.

EDIT:

Thank you PrismalDawn, I just remembered something else that pisses me off

Fighting in the middle of nowhere. Near the dragon pit when Dragon's not spawning for another 3 minutes. In the middle of mid lane with no towers anywhere nearby. Chasing enemy champions into unwarded territory to get killed even though there was nothing to gain for killing somebody there and then anyway.

Less to do with people not knowing how to play behind, but MAYBE the game won't feel so damn snowball-y if teams stopped getting aced for literally no reason.

EDIT:

Ooh, another thing.

When a laner dies before the Jungler even has a chance to clear their second buff and are spam pinging the Jungler to come save their lane for them. At the same time though, they seem to be doing everything in their power to make it as difficult as possible for the Jungler to gank, all while blaming the Jungler for anything that happens all throughout game. These guys are almost always the same people in my first example - building damage, getting into fights they already should know they can't win, and then losing lane even harder than before. They can't manage their waveclear, they can't call out warded routes, and excuse you if their laner came to your lane without any warning or MIA pings.

On a similar vein, people expecting their supports to cover for their shitty plays. I realize Braum's theme is Stand Behind Me but can you stop sacrificing him to the enemy team every 5 minutes?