The contrast thing is only to stretch your perspectives, it's not about good or bad, it's about understanding other perspectives and the minute shades of grey that you might eventually see. Regarding extremes, it takes time, DBT is Dialectal behavioural therapy, but the more important part is the word: DIALECTAL, because it sums up to two truths, because two things can be true at the same time, someone can be irresponsible and kind, or mad but mean well. This is something that takes time to practice and focus on, it's taking me 3 years, and I'm probably 50% there. And positivity isn't always good, sometimes it's better to see bad and understand that it's bad. If you're always happy, you're in denial or perfect, and I trust neither, but if you're happy and sad at times, that's the only thing that's reasonable. Quick last note. Practice doesn't make perfect. It makes permanence. Remember that till you pass.