Interesting thread, "hate" is a strong word though, i do not think i am capable of hating someone just because i dont like their music
When it comes to names, I see a clear pattern with several producers: Once they appear in the scene, they create some wonderful music, but very soon fall into stagnant producing either the same track over and over again or just lacking any creativity.
Markus Schulz is great example here. Once he appeared into scene until 2005 "Without You Near" (which was one of my favorite albums and brought sort of new style to trance), he hasnt produced anything interesting. It has been especially terrible in recent 5 years.
Same with Aly & Fila, really liked their first album, nothing interesting since then as it is sort of just reproducing the same tracks.
Can easily list like 10 producers, who fall into same category, John Askew, Gareth Emery, Andy Moor, Simon Patterson, John O'Callaghan etc.
And of course there are producers, who I never liked, not a single track, but for some reason became really popular, Bryan Kearney, Arctic Moon, Allen Watts, ReOrder, RAM just to name a few.
Giuseppe Ottaviani is interesting case though, he was for years on the previous list, but in recent times, he has produced some really interesting tracks, so unlike most, I have really started liking him much more.