I play solo, though sometimes with a friend too. I've noticed more and more recently that I'm constantly in games of 3 or 4 premades vs the same on the enemy team, and its some of the most anti-fun games I've ever had. People play with their friends and then just ignore the other player. I rarely receive ganks, help, buffs etc, where I would normally get them in a team of solo players.
I know riot likes teamplay etc, but its hardly fun to be completely isolated and ignored for 45 minutes because I didnt queue up with. It should be down to whichever team is better, not whichever team has more premade members that just cheese you with 3 man ganks etc all the time. Never noticed it to be a problem before, but in the last few months its getting way out of hand.