People are ♥♥♥♥ at the game, they fail in their safelane and expects the solo midlaner to come in and magically fix everything they have ♥♥♥♥♥♥ up in that lane. The offlaner fails to understand that his role is to soak up experience. If dual lanes are run, both lanes expects mid to come and fix things when they eventually ♥♥♥♥ up and lose their lane. If mid loses, he'll blame the sidelanes for not calling miss, or some other retarded reason.
Point is, people fail to realize that when they lose their lane, it's their job to find something else to do, they can't just yell "mid come gank" and everything will suddenly be better. The supports in your trilane should gank mid and offlane, the support in your safelane and your jungler should gank the lanes. There is no clear answer as to who the "gankers" should be, if you are losing your lane, you should probably be the one ganking and not the one requesting ganks. If you're support in a trilane, you should be the ones ganking. If you are a jungler, you should gank and put early pressure on lanes if needed.

The midlaner is in my opinion the only one who shouldn't be running around ganking, unless he is in an unfavorable matchup and can't get anything out of the lane. This is because the areas around the midlane, is so crucial for you to control in order to win the game. It also depends on the midplayer, some people have a tendency to win unfavorable matchups just by outplaying the other midplayer, and in these often prefer to stay in their lane because they get a lot of kills and cs just by staying mid. Some people prefer to gank with heroes like invoker and SF, despite most players having a more passive role with these heroes mid.
tl;dr: when people lose their lane due to an "unwinnable matchup" and continue to stay in their lane yelling "i need ganks", then they are the ones playing the game wrong. If people lose their lane when they should be winning, and yell "need gank", then they are the ones getting outplayed and should leave the lane trying to do something else. People in 3k pubs just fail to adapt and refuses to play the game any other way than how they prefer to play it.

I've played a couple of AM games were I went "I'm not gonna get anything out of this lane, I'm just gonna get some quick last hits, buy brown boots, and leave the lane." So basicly I abandoned the safelane 3 mins into the game because I just couldn't win the lane against heroes like Huskar, and a tiny/ogre combo, without having a really solid trilane, something I didn't have. I roamed mid, secured first kill because noone expects a level 2 AM to blink into them and mana burn them, continued to roam, soaked up farm in empty lanes and small camps in jungle, and made sure we won every other lane. In the two games I've had to do this, I ended up with decent farm and solid contribution, we won both. So yeah, when people go "mid no gank gg" they are just too bad at the game to know what to do, when things didn't go as they wanted.

Emp tornado ♥♥♥♥♥♥♥♥ and cold snap necro spirits combos. Also fed voids, moonlight shadow, witch doctors look at it go thingy, skull basher item, batrider napalm, beastmaster roar, luna ulti when you try to gank her in the jungle, all composite damage, bristleback, lanes requesting ganks, slardar and spirit breaker bash, slark, counterpicking, playing against axe in a dual melee lane, russian 4 stacks, death prophet ult, rubick because he is spazzy as ♥♥♥♥, spirit breaker charge, nyx, riki, bounty, clinkz, chainstunning, windrunner shackle ♥♥♥♥♥♥♥♥, shadow shaman, nature's prophet when you don't counterpick him, all silences, necrolite aura, viper, venomancer orb of venom, sniper headshot, kiting, drow's 90 second silence, pub lane combos, 3 2 parties against one 5, matchmaking, peruvians, pudge, tinker permahex, shadow blade, all evasion especially backtrack (duhhh iz not evasion), people who does not speak english, spanish people (i have private reasons), all invis heroes, wards, smurfs with 5k hours ingame, low priority, steam servers, icefrog, iceiceice because his name reminds me of icefrog, all pure damage, lich aghs, illusion heroes, skillshots, techies, escape "mekanisms", blink dagger, denying runes, centaurs in the jungle, mud golems, ancients, dire side, pudge fountaincamping, trees regrowing, timbersaw, chaod knight, fade bolt, naga song, teleport scrolls, roshan bashing, playing against outworld devourer as phantom assassin, playing anything against outworld devourer, all slows, gyrocopter missle, black king bars, lycan split push, lvl 1 rosh in all pick, all initiation spells, linken's sphere, weaver, fissure, earthshaker, earthshaker carry, miss chance, monkey king bar? Secret shop, the shopkeeper, fountain healing too slow, sunstrike, all global abilities, trees, playing against doom, playing doom, jungle wolf aura, rng, high damage nukes, lich in the laning phase, treant dd rune, ranged heroes, orb walking, creep agro, tower agro, playing against meepo, getting counterpicked as meepo, ganking, people who say double boot is good, people who don't dissasemble their arcanes for bloodstone, necro ult, radiance, doom agh's, ogre magi, multicasting, untouchable, loda, dendi for making pudge even more popular, wisp hero dual lane mid, juggernaut tri-lanes, decrepify, any magic damage amps, mekansm, battery assault, kunkka cleave, x marks the spot, split shot, boner king, legion commander, bane and mirana, batrider lasso, primal split, illuminate, decay and ofcourse ♥♥♥♥♥♥♥♥♥♥♥♥♥ homing missile, you know its coming and you try to run but there is no where to go. Its hissing noise alerts you of its presence as you wait in dread to see that you are its target. It approaches you slowly, menacingly, terror fills you as it homes in. You run, knowing that each step you take only makes fate's thread unfurl faster. The accursed harbinger races even faster, the hiss of its propulsion grows louder and louder as your death approaches. You are almost there, the safety of your base beckons towards you, you've used up all your escapes in a fit of panic, but none can cease the march of the rocket. Then it crawls right behind you, the audible bonk reverberates your very being and their team closes in on you as you lay there helpless, counting the last paralyzing seconds of your life. In the brief flashes prior to your death you see a figure in the distance. The old ♥♥♥♥♥♥ stroking his virulent moustache.

tl; dr i hate this game

Why I hate Rikimaru (aka trash tier hero)

Riki. Such an easy hero to counter, but even if you purchase detection because your supports are rushing aghs, and try to play a roaming 5-man there will always be that one guy with terrible game sense and positioning who will feed relentlessly and blame your team for his own incompetence. It's just so, so easy to capitalize upon bad players team play and individual play as riki. Its frustrating because his invis should be meaningless vs a coordinated team.

People in that your think theyre the holy saviors of mm system when they pick supports when in reality they sit behind the carry on lane in full vision every game, leech his exp for 10 minutes and deny creeps (wow such impact) then wonder why their team isnt winning the game for them