inconvenience
Something that causes small trouble or extra effort.
An inconvenience is something that causes you trouble, difficulty, or extra effort, even though it's not a serious problem. When your favorite pen runs out of ink right before a test, that's an inconvenience. When the library closes early on the day you needed to return a book, that's an inconvenience. These situations are annoying and require you to adjust your plans, but they're not disasters.
Inconveniences don't fit into your plans. They're like small obstacles that pop up unexpectedly. Maybe the store is out of your favorite cereal, so you have to choose something else. Maybe your regular route to school is blocked by construction, so you have to take a longer path. Maybe your internet connection drops right when you're trying to submit homework online.
Notice that inconveniences are manageable. They might frustrate you or slow you down, but you can work around them. When something becomes more than an inconvenience, we usually call it by a stronger word: a problem, a setback, or a crisis.
People sometimes use inconvenience as a verb in a polite way when asking for help: “I'm sorry to inconvenience you, but could you help me reach that book?” They're acknowledging that their request might cause extra effort.