For me its hard play to as a black against English opening, and as a white against Sicilian defense. There is a lot of side ways, variations ...
most feared openings?

Usually the stuff I don't see very often, because I cannot remember what I am supposed to do against it and end up worse somehow. These lines usually include the alekhine, nimzowitsch, latvian and elephant gambits, some lines of the scandi, the modern, the petrov, winawer sidelines and probably some others. As black I get into trouble against anti-sicilians sometimes, as well as anti-dutch lines. I just need to review these openings more often, especially after playing against them.

As white, I hate to go up against the Petrov, not because it's supposedly drawish, but because I allways go down in flames against it.

When I played the Sicilian I had to get a book on the anti-Sicilians, but players of 1.e4 seem to have an even rougher time against the French. That makes the French worth playing IMHO.

As black, the London and the Veresov, as white, since I play 1. c4, I usually don't mind what black opens with.

i love when people play the sicilian against me, because then I can play the morra gambit!
as white: i hate playing against the petrov, the french, and any of those insanely sharp countergambits, like the latvian, the elephant, or falkbeer
as black: people who open with e3, and then bring the queen to h5. its so stupid, just pisses me off. i hate when i play the french, or the caro-kann, and white immediately exchanges pawns. ruins all the fun.
yeah as white i hate the caro, but against the french i do this 1.e4 e6 2.d3 d5 3. nd2 then transpose it into the KIA. now that i think about it you can do this against the caro also. its very solid for me. then as black i hate the c3 sicilian it pisses me off.

I don't worry too much about that as I play g3/modern or KID or KIA pretty much exclusively unless it's a lower ranked player than I just go for e4 crushes... :)
I am wonder what openings do you NOT like being played against you. As white I have seeing black pull out the french (I play 2. Nf3 to avoid it, or exchange the pawns). and I also hate the petroff in must-win situations, (will play the KG or QP if opponent is a known petroff player).
As Black I do not like the KG (though I like the Fischer defence). it is awkward to play with.
what about you guys?