Haven't played ranked, but I know how you feel. I had two games where I got Bot in the roulette and the top asked to swap so he could duo with the support. In both games I played Nasus (since I don't play top) and just farmed as "An ally has been slain" or "An enemy is godlike" rings in my ears. Even as mid I've had games where I'm even or slightly ahead and you'd swear bot lane is just suiciding cause there is no way someone can die this quickly.
I think a lot of it is that people don't realize how "difficult" (that's no the right word, but I can't think of anything better) bot lane can be unless you play it. Yeah, there are two people there, that means you can die twice as quickly if you don't play right. Heaven forbid the enemy jungler/mid comes and you aren't immediately under your tower.
: : Rant-ish incoming : :
You also just get the ADCs who want to play the "broken" champ who has never tried them before. "They have two tanks, I'll pick Vayne." Great pick into the Caitlyn... Or they die early and then keep fighting thinking "we can turn this lane around" instead of just farming safely. I've had so many ADCs walk up to get that one CS only to get insta-killed by the enemy team. Let go of that CS and stop dying, that's your only goal now. I even had a game with 2 AFk's (our jungle and support) where I was 2v1 the whole game. I had the worst CS ever but I only died 2 or 3 times and got something like 5 kills, one even being a double when I was ganked under tower. It's not the hard to play safe. Or worse is when your bot lane is ahead and the ADC takes that to mean "I can 1v5." No, you can't, stop walking up to their second tower when you don't see any enemies on the map.
On the other side, you have the supports who do nothing all lane phase and just let the ADC 1v2 while they leach experience. "I don't care that you picked Janna to disengage. You have a Spellthief. Go auto someone or apply some pressure for heaven sake. Stop standing 5 feet behind me while their Blitz is charging us." Best yet was the Braum I had who did nothing all game but kept attacking me for getting hooked by Thresh or not walking close when he got hooked so he could jump to me. Then you have the "supports" who don't seem to know what a trinket is or that warding is important, and seem to believe they are a second APC. I've had games as the ADC where I warded more than our support who had a sightstone.
Best yet is when the lane sabotages each other.
Supports who steal CS or just blindly auto minions while the ADC is trying to last hit are my favorites. If the enemy is dead, fine, help me push the wave. But if both are sitting there CSing, I'd rather you auto one of them instead of the minion I was gonna get. If it's not possible for me to get the CS, fine, take it, but don't blow 2 abilities to do it.
ADCs who can't CS just drive me crazy though. I've played so many games where I watch my ADC basically park in the middle of the minion wave and just let their character auto, missing 80% of the CS, while also getting hit by a lot of enemy damage. Yeah, I'm a Soraka, but I'm gonna run out of health or mana if you keep eating all this damage.
Then you have the people who don't know their limit. If you are at 200 health, you may want to base unless you are/have a sustain support. I had a recent game with an enemy blitz who I got down to maybe 200 health before deciding not to chase him any more since I didn't want to get pulled under tower. Went back to CSing and he's still there, under tower, channeling recall and then canceling it only to laugh. The minions got him down to 50 health at one point but I just waited. Eventually my support hit a knockup and I got the kill because he just wouldn't go back. I think it was 3 or 4 waves he sat there at such low health hoping to bait me in. On the flip side, I had a Bard who would land a stun on the enemy ADC and then get hooked flayed and chunked to 300 health who just wouldn't leave my side unless he was getting chimes. He died something like 5 times before the enemy took our outer tower. I even had a game as Orianna mid where I probably tilted the enemy cause they would drop everything on me and I'd still live with 10 health 3 or 4 times despite them tower diving and everything.
There's a lot of team work in bot lane that gets ignored because people don't understand it. Support is not a glamorous position cause no one really notices that you are doing your job because no one on your team dies if you do it right. In the same boat, the ADC gets all the credit despite the fact they may or may not deserve it. In one game as Lulu support, I saved our Ahri mid who got dove under tower by Amumu because I got there in time to exhaust and drop everything until she came out with the kill. Did the same with our Draven who got three man ganked since he was too far forward by flashing in, exhausting, and dropping every ability until he came out of it with a triple kill. Both times they acknowledged that I saved them, but normally that's not the case. I even just had a game as Miss Fortune where I ulted to kill one and whittle down the 4 tank enemy team (Rammus, Tahm Kench, Alistar, tank Akali, and Ezreal) just to deter them from attacking and my thresh (earlbiff) got a hook on the Akali that kept her in my ult so that she died also. I did not deserve that kill but I got credit for it despite him being the reason it turned out that way. We won off that play despite it looking like we were going to lose early because we had some great teamwork.