The ways in which each of you thinks provokes irritation in the other. You're more intellectually daring than this person, more comfortable with abstract or unorthodox ideas, with taking leaps of faith and changing your mind as many times as is needed -- which could come across as annoying or even threatening to your partner. They prefer to take more standard paths toward solving problems and don't want to change their mind once a decision is made.
That more traditional point of view feels limiting to you. You operate on a more intuitive level than they do, while they rely more on logic -- and you each wonder why the other isn't more like you. Arguments erupt, you each take your standard position and it's hard to find a resolution. Worse yet, you, with your more creative point of view, could end up treating your partner as if they're stodgy and unimaginative, which is both inaccurate and hurtful. Working together is really difficult because of these differences between you, especially for your partner, who finds your erratic energy to be too much to handle. You have to learn to respect one another's point of view if you want to make this work; otherwise, you just end up making each other feel uneasy and unappreciated.