For example, I used Amazon Elastic Transcoder to do video compression/transcoding at a previous company thinking that we would save a lot of time but the API wasn't great; a lot of the default settings weren't right for our use case and the API and notification flow was way more complicated than it needed to be and prone to errors (due the the sheer complexity of input parameters it could handle).
At one point, we had a problem receiving SNS notifications from the transcoder and we didn't know what was causing it because we couldn't effectively access/browse the error log and was was exposed to us wasn't detailed enough. Basically the visibility in Amazon-land wasn't great.
We had to pay Amazon for special support so that they would tell us what the error was (after weeks of back-and-forth).
Now that it's all running, it's fine; so long as we don't need to change anything and don't need to start scaling up/sharding the pipelines; no sure how to do this through their UI.