Where's your proof that most hate them most? If you'd asked everyone I'm sure you'd have collected data on 2nd most hated along the way.

I don't like gremlins, see: http://forums.spiralknights.com/en/node/88801#comment-785605
2nd most, more gremlins.

I'm thorn between gremlins hiding in corners with their shields or wolver teleporting all over the place pointlessly.

They are harmless but hard to kill, the wrong way.

Monster FAMILY? I don't hate any families. I don't even hate fiends, just specific KINDS of fiend.

Almost every single monster in the entire slime family. I HATE them. Glop drops are the worst.

RocketPuppys and Howlitzzers are pretty annoying, especially when you got someone just spam killing howlitzers, the run past you...

If I had to choose a family, it would be Constructs first, then Undead.

Well if we're talking specific monster classes, I would say Lumbers. They break virtually any shield in one hit, stun nearly if not 100% of the time, AND inflict a SECOND status at the same time at nearly 100%. And their only attack is deceptively fast and has an absurd hitbox (I've been hit when I was two full tiles perpendicular from the "club").

Get hit by a Silversap even once, and youre pretty much dead. And before anyone rushes to insult my skill, I'm not saying they're unbeatable, I'm saying they're annoying and cheap.

^ Thats why u gotta dodge em. And that is also why they are insanely slow.

Worst family are slimes

Next would be fiends

Everything else is so dumbed down that if you try and die, you should really just quit. Undead used to be a challenge, but suck for example.

Slimes?!?!?
You must be crazy or something. Slimes are like the easiest thing in game.

1) Wolvers are a piece of cake. Equip one item with Pierce resist and get a Flourish. Or be Shard Squad awesome and spam DBBs everywhere. Also with Chromas.

2) Same for Slimes. But bring any 5* Brandish and any Driver and you are set for them. DR and Sentenza work well too.

3) Constructs are slow and easy. The occasional Blight/Cryo Knight is a bit annoying, but still easy. Get a Combuster and teach 'em who is boss.

4) Gremlin Menders are the only hard ones. Thwackers are easy to kill with Achreon (and even Combuster lol) charges, just don't let them go to corners. Knockers are the easieat enemies in the game, as I have yet to take damage from their small hitboxes. Bombers can be annoying in small boxes but anywhere else are easy if you bring a Callahan, Umbra, or Sentenza. Scorchers are pretty easy, just go behind them whenever you use attacks. Ghostmanes are easy if you have DR/Shards/Shiver/VT/AoA/SS/VV. +Gremlin Mender

5) Zombies, Kats, and Howlitzers are easy, just Brandish charge and shield. Crusaders take a bit of work and kiting, but are not too hard. Bombies...ugh. This is where the Undead are annoying. They 1) respawn and 2) still explode after you kill them. Phantoms are annoying too, but unless you solo, they take a long time to kill. +Phantoms and Bombies

6) All of dem are annoying. Five star Flourishes and Blitz Needle won't kill these...fiends. Devilites are dodgy-mobile-turrets, Gorgos track you while they bite, Greavers are super annoying and won't let you charge anything (tried to use my Fearless Rigadoon on it but they don't get flinched, and Trojans can now survive Blitz charges. Silkwings are easy (unless they respawn), but the rest are annoying. +Devilites and Gorgos and Greavers

7) +Grave Scarabs. Those are annoying as the Core. Their attacks are worse than the other two minis.

So the second most annoying enemies are...Mini Jellies!!! Why? Because they only take like 30 damage from a DR and are immune to the orbs, and their damage and clustering is annoying. That wraps up our so so stay tooned for another episode!!

Well I'll just follow suit and ditch the whole "second family of monsters you hate" and just substitute a list. To each his/her own, hm?

1) Greavers, because I have no idea what I'm doing and panic spam until I die :D

2) Rocket Puppies, especially when there are multiple at once. Their guided rockets stay live for a bit too long and can take all the time in the world to guide. Not to mention that they can spit them out pretty fast too...

3) Ice Lumbers. They'll literally hit you up for a nasty perpetual smash combo if you don't get unfrozen somehow or go invisible. On solo these are nearly an instant death if you get snagged, usually a one-hit shield break even on my Heater Shield.

4) Gremlin Hordes- These happen when your teammates decide to round up all the stray gremlins in a Decon zone and try to kill them. There's always at least 2 menders in an army of Thwackers, and it's hard to get close with their staggered attacks and constant healing, even with Maskeraith's help. Luckily these are somewhat rare.

I find beasts the absolute least annoying family. Their piercing damage doesn't do a whole lot with my Skolver coat, and they're in their own way slow and very predictable.