Cognitive Behavioral Therapy (CBT)
Everybody has "blindspots". Increasing self-awareness of your internal processes will allow you to see clearly that you are never as "stuck" as you might feel.
CBT is life-changing because it provides very specific and pragmatic skills for feeling better and re-wiring the brain towards more healthy and balanced thinking.
If you're the kind of client that likes having organized approaches and concrete tools, you'll find cognitive therapies to be the most rewarding.
CBT tools and knowledge are also incredibly valuable in relationships, because they result in more effective articulation of feelings and therefore more productive and empathic communications.