I’ve played now all the leveling dungeons up to Brayflox’s Longstop several times each, mostly as caster DPS (Arcanist/Summoner) but also occasionally as healer (lately Scholar). So far of the 20 or so dungeon runs I’ve been on I’ve only had one mildly negative experience, annoyingly that happened to be the first run for my husband’s new character of Satasha.
There was some banter at the start after an overpull and wipe but after that was sorted out the rest of the run was smooth enough. Most runs are actually pretty friendly also in my limited experience – people say hello at the start and thanks at the end. There might be the odd tactics discussion also. It’s nothing like the horror of completely silent runs in World of Warcraft’s dungeon finder when it was introduced in Wrath of the Lich King.
My most recent dungeon runs have been absolute pleasures, with courteous, helpful players and people eager to learn their (new) class and the mechanics. I really enjoyed running Halatali for the first time, which also gave me the necessary kills to finish my Grand Company hunt log.
I’ve read on forums that it’s a different ball game in raiding since that’s more high pressured with tougher mechanics and greater rewards to lose out on. Regardless the group content in the game that I’ve seen so far is good fun and there’s plenty of it. Fates are also an ever-present distraction if you choose to do them, just like the titular rifts in the Rift MMO.
I think Square Enix has a nice balance in the game at present of group content of different difficulties. There really is something for everyone: formal dungeons and raids for the traditionalist and public quests (Fates) and Hunts for those who embrace modern casual grouping.