I think the parts of the job that he hates are the paperwork and that it takes away the time he would otherwise spend with his family (thus straining his relationship with Boruto). He wanted to become Hokage to earn the village's respect, but he did that during Pain's invasion, and solidified it during the war. Nowadays, his motivation probably has something to do with protecting the village since he considers everyone in the village family and he saw so many fellow ninja die in battle (one of which sacrificed his life purely to protect him and Hinata).