I really, really, really hate 4 mans.
As a jungler, it seems like a majority of my games are playing with 4 mades. You can always tell even if they're not rocking the same tag; the enemy team is EXTRAORDINARILY well coordinated, and your teammates will never talk, ping, give any indication of what they're doing, and least of all cooperate with you.
It's tolerable during the lane phase. Not great (because if its a multi-person fight you're immediately at a disadvantage, from being the pug), but you can soldier through it because they GENERALLY try to cooperate with you.
Once lane phase is over though, it's nightmarish. The total lack of communication, lack of them acknowledging your calls, and lack of giving you any calls, leads to the game degrading VERY quickly even if you've established a rock solid lead for most of your team.
Once in a blue moon this isn't true. I've had a few four mades which worked with him, responded to my calls / made theirs clear through pings or chat, and were really enjoyable. That's maybe 1 in 25 four mades.
It's genuinely enough to make me not want to jungle; it's that fucking bad most of the time.