When I first started playing League of Legends, I would build Catalyst of Aeons because I would run out of mana too fast. Another thing I remember was when I called this Yasuo out for hacking because he was getting double crit chance. Those were the times.
Friend: "Hey, you have 4000g. Why didnt you buy at base?" Me: "I'm saving up to buy a new champ".
"Trinity Force is a good item because it's the most expensive"
I remember wondering why Katarina built magic damage. She did her damage with daggers and shit so i thought she was ad.
Flash into walls. I used to do that but I still do that too. :P
I built warmogs first on Twitch. I'd ult minion waves as Twitch. I thought a shaco was hacking for having 2 versions of himself. I thought Aatrox was a viable champion. I built the old corrupting potion on Aatrox, even though he was manaless, because I thought it was worth it.
Cancelling my own channeled abilities by walking
"I don't need starting items or health potions, they just slow down my build"
"They can't kill you if you stack hp 
"
My friend told me to stop focusing the tank as Fizz.
"I'm not focusing the tank, I'm trying to burst down this blue ninja guy but he won't die!"
I didn't buy items because I didn't know shop was a thing.
"who needs a map? I know where I am already..."
I never realized you could by components, so i waited till the full item.
When I me and my brother first started playing, we always took smite because it said "1000 true damage". So we always took it, tried to use it on enemy champions. Soon, my brother became frustrated, so I told him "they just have to stand still".
I played mainly Soraka vs Bots until level 23-25 because I was simply scared I would suck and to be flamed in a actual PvP game.
Nothing I was a pro my first day. Lol no but seriously the first time I played league I didn't use qwer, I just played tristana and pressed the buttons at the bottom of the screen. The sad thing is it was working
I thought it was more expensive to buy component items so I would only buy the fully-built item outright
Zed jungle. But this was no ordinary Zed jungle (as if Zed jungle is ordinary). I would call jungle in champ select, lock in Zed, and then I would run to bot lane. Once I got there, I would sit in one of the bushes and just harass all game. Bush=jungle, right? Nothing else. Never even touched the jungle monsters. I also had no idea what Zed's ult did. But I still loved that champ to death, him and Jinx were my favorites initially (still up in my top 20 nowadays).
In the five or so games I did this, I'm pretty sure I had five different builds. I remember very clearly that one of them was a relatively normal build ("relatively" being a relative term here), one was a full AP build, and one was a full mana build.
Buy xp boosts so I could "out level my lane opponent"
I don't remember the stupid noob builds I probably had, but I do specifically remember thinking Smite was better than Ignite because it did more true damage.
"Why are these "junglers" trolling? don't they know its supposed to be duo top?"
"I should take this AP item on champs to make there abilities stronger"
"Teemo was made to be support"
"Why doesn't Garen's Ult kill anyone?!"
Ah, good times
[zombie-nunu-bummed]
Stacked 
Also, team: "fiddle, are you starting blue?" Me(fiddle): "what is blue?"
I would use Ashes E in a fight because i thought it did damage
i used to build 4-6 needlessly large rods cuz im like "omg look at all this flat ap its BUSTED!" also my friend told me to build runnans and stack warmogs on zilean
Tried ulting the tower as ashe.
I played Karthus.
I used to press all of my abilities in one trade. I always had to.
I used to wonder why the ultimate level sign was gray when I leveled up. I thought my game was glitched.
I would save up to buy an item at full price. Recall -> Check gold -> See price -> "Ah, I need around 1.2k gold. Back to top." I remember complaining about how expensive items were and how people got them.
Thought Smite was the most OP summoner. Tried it in a bot game. Never worked. "Looks like a bug or something."
build multiple 
s for late game mana sustain as 
.
on any lane cuz it has +2 gold/10sec attached to it.
Took pre-rework 
on any champ cuz it had +3 gold/10sec attached to it.
"Yi is such a broken OP champion"
-Barkley, 2010
Hmmm, I'm running out if mana, and I'm dying before I can do enough damage with Drain
Tank Talon. The items vere 
( mana issues )
. Yup all those items on 
. I belive the mindset was ,, WELL I AM AN ASSASSIN, I DO DAMAGE AND THEY CAN NOT KILL ME IF I BUILD TANK.,, YEAAAAAAAAAAAA
In my defense, this was old Talon and Lethaliti was not a thing then.
TAKE THAT RIOT I BEAT LEAGUE OF LEGENDS. TANK TALON META.
To all the people who played with me then I AM SO SORRY.
I didn't know what an adc was, so I thought it was just another name for bot lane And with my stupid logic I thought since it was the bottom, the mid would be adb and top would be ada So when I would call "ada" in champion select so many people got confused
Built attack speed on everyone. I thought, more attacks = more damage. I mean technically I wasn't wrong. I watched pros play to understand the game.
-Trying to shoot people with the Ashe hawk-shot for damage. -Thinking that undying champions (Anyone with a rebirth passive, including old Zyra) were inherently op. -GA second item so I'd die less.
I'm the only one who leveled up with bots until lv 15?
Who took smite for the cannon minion because lasthitting with Fiddle is difficult?
Who practiced flashing over walls after the inhib fell?
Who took tp/clarity on supports (and people were actually grateful)?
Who didn't know Janna's ult heals you until he blew it for fun when the enemy team ff'd?
I don't really recall anything that stands out, aside from occasionally losing track of my champion in a team fight, more then a few teammates got annoyed at the Gangplank standing 3 feet away that wasn't doing anything while they were getting jumped.
EDIT: Oh yeah, and I'd stare at the shop for like 3 or 4 minutes trying to figure out what to buy.
I got confused for the longest time why my Lost Chapter, Etc., would disappear when I bought Morello's and other items. Because of this I would sell Lost Chapter and other stuff before buying the main item because I thought the item just got deleted and it would be a waste of gold.
Pantheon was destroying me and I was teemo. So I was like "oh he wont hit as hard if I build 
"
What a silly time
"but muh last hits."
