Try and investigate the thoughts behind the emotions, including asking "why?". Don't repress the emotions and sometimes it's good to let them out, but you want to be diligent in being aware of the predictable mental stories that repeat (conditioned habits). You want to be disenchanted with them because they will not make your life better. Look at them as mental habits that as you interrupt over and over again you can notice the feeling tones pass away on their own and over a larger period of time they weaken from a lack of further conditioning you prevented. Those feelings give the thoughts (logic and reason behind the emotions) gravitas. When you don't add to the stories they lose gravitas. Ask "why?" 50 times, 100 times or as many times as you need to until you feel better.
I think it's good to use concentration practices here and there because you can feel the attachment let go further. The brain sometimes only lets go partly and by letting go completely (or as far as you can) can you see how built up the attachment is. Other games like playing hide and seek with your perceptions and mental stories can give you that readiness for when they arise. You can see the mechanical wheels turning when the perception of a dislike turns into a story. You can go "a ha!" "There you are.".

Other tricks like trying to make yourself more angry or more sad can interrupt the mind stream.
Try and rate your mind as valuable real estate and rate thoughts according to their usefulness. Realize how quiet your mind will be when those thought habits are gone.