I have played quite well in a lot of games and yet still been unable to win due to teammates being horrendous. While I do accept that I may have an over-inflated view on my worth in a match (I think I should be somewhere in the mid-Silver range) there are quite often times I just can't save a game. When my team is 3-15 (And all the kills are mine) within 6 minutes, and just constantly feeding, I can't keep all three lanes alive, let alone clear the jungle camps I need to in order to get the exp/gold to progress. I was 8-0-1 the other day at one point in a match, but every single time I left lane, the laners would die. I'd go gank top, they'd get a double-kill on my bot. My ADC and support would cry about not ganking for them (I'm level 3 and have already gotten 2 kills, one in top, one in mid) so I go gank bot, got one kill and my mid-laner died and starts spamming pings for support. As a jungler, if you don't have at least two lanes that hold their own for a couple minutes at a time, you can't win the game. Same with one of the games I played last week as a top laner. I won my lane, HARD. Playing WW top versus a Jax (Which is generally considered a tough matchup for WW, from what I have seen) I solo killed him twice in the first 6 minutes and was 4/1/2 at the 20 minute mark with an assist on the enemy jungler and a roam to mid to help out and a teleport to bot to save them and a huge CS lead. I ended up going 10/4/7 (With the 4th death coming in the last 30 seconds trying to defend base) with 181cs (To 131 for my opposing top laner, I was 2nd overall for CS with the enemy ADC having 211 and nobody else being over 134). The least deaths among my teammates was 10. Everyone else was higher than that, I actually had the least deaths overall of ANYONE, with the enemy midlaner being 10/5/7 (Same kills/assists, 1 extra death). The statlines of the teams was:
Enemy Team
TOP - 3/8/1 (131cs)
JG - 9/6/6 (133cs)
MID - 10/5/7 (127cs)
ADC - 19/11/11 (211cs)
SUPP - 7/6/20 (74cs)
My Team
TOP - 10/4/7 (181cs)
JG - 6/11/7 (65cs)
MID - 4/10/8 (134cs)
ADC - 9/11/10 (90cs)
SUPP - 7/12/16 (84cs)
Worst, my support was flaming me because I only teleported down there once, even though I only really had one opportunity to do so, they were dying way before the engagement would have given me time to back out of lane and teleport. The only way I could have helped bot any more would have been to give up top and just give us a 3-lane bot (Although I offered to 1v2 lane bot if they wanted to go top). As it was, the enemy team had already killed the bot inhibitor tower pre-20 minutes, before I eventually lost my top tower to the Jax and Yi...
who says it's her first time playing, then I see a 
who doesn't know how his passive works, then I see a 
mid building AD.
and a veigar adc ... and he says that's ez carry with veigar supp