It only matters when someone wants to make their dislike of you your problem.
I competed in roller derby with a guy who told me to my face he didn't like me, but he was respectful and never withheld coaching, scrimmaged with me and was a good teammate, and we otherwise just stayed out of each others' space. We just didn't have personalities that meshed.
Then I'm not in sight anymore I circle back around and follow them to their car, noting their plate number to I can pay a police buddy to get me an address. The I follow them to until I know where they work and what their job is.
Then I take on training and job experience that would make me a good manager for that type of work, and monitor job postings at their company until I see my opening, nail the interview, and become their boss.
At this point, they've likely moved on and forgotten who I am.
But I haven't forgotten them.
I proceed to make their job miserable and impossible, until one day I call them into my office to explain that why need to let them go for poor performance. Then I lean way in, right up in their face, and say quietly "And, to be honest... I don't like you."
Then I quit and go back to my normal life. No sweat off my back.
Don't respond. Anyone who feels the need to express that is just looking for a reaction. Don't indulge them. When people genuinely dislike someone they tend to only interact with them when absolutely necessary, so if they're volunteering the information without being prompted it's only for a reaction.
@Veronicaella "Well ain't it a good thing I don't value you're opinion". If they already think you're a cunt you might as well embrace it by saying something equally obnoxious.