A makeup flop is usually a personal thing, it's not necessarily that the product is bad. Often times, it's just that it didn't work for your skin type or tone, etc. I have a little mix of both this month.
I was excited to try the Milani HD Advanced Concealer as it had been compared to the likes of the YSL Touche Eclat, but obviously at a much lower price point. My biggest disappointment was the oiliness of the product and how dark it is. When first swatched, it seems somewhat light - similar to a foundation color for me or a touch darker. However it oxidizes downright orange on my skin. Just couldn't make it work, darn!
Here's the fresh swatch on the right, eyebrow marker and lipstick to the left.
foundation swatch post I had also swatched the Milani to compare shades, I let them oxidize and saw how much darker the Milani had gone.