One of the questions on my survey asked X (which can be important for my research), and most of the participants answered "average" - I'm a bit lost with the outcome. What can I actually say about this respond?

e.g. Do you find X difficult
90% answered average.

To be honest, you can't really infer much from this unforunately - just that pretty much all the participants responded the same way to this question. As survey questions are used to differentiate between participant's feelings/views/beliefs/knowledege (whatever your survey is measuring), it would suggest to me you should not include this question in any further analysis, but simply report it as you have done above.