The unappreciated average

I can't carry a tune in a bucket

Not trying to being mean but mediocre talents are generally talents that people never put the effort in to get better. Now, I'm basing that on the premise that talents are natural abilities in any given area. Not to be confused with people that never get great at something they've put alot of effort into. If you're mediocre at something you've put a ton of work into that just means you didn't have a talent in that area. That doesn't invalidate your ability, it just means you didn't have a natural talent in that area. Plenty of the greats didn't have talent in their areas but through massive effort and good teachers they've bridged the gap between the talentless and talented. The downside is that if a talented person puts just as much effort into it they'll most likely be that much better than their counter parts.