About what "quick-failing" reeally is for 

efore conducting an extensive review, and after ensuring you are viewing an unvandalized version, check the article and its edit history for the following basic problems which are sometimes found in GA nominations.

 The article completely lacks reliable sources – see Wikipedia:Verifiability.Small articles that have a single main source may still be adequately referenced without the use of inline citations.  Inline citations may not be required for some articles; the criteria name the only six types of material that require inline citations.
 The topic is treated in an obviously non-neutral way – see Wikipedia:Neutral point of view.Articles on controversial topics can be both neutral and stable, but this is only ensured if regular editors make scrupulous efforts to keep the article well-referenced.  Note that neutrality does not mean that all points of view are covered equally: instead no point of view should be given undue weight.
 There are cleanup banners that are obviously still valid, including , ,  or large numbers of , , or similar inline tags. (See also .)
 The article is or has been the subject of ongoing or recent, unresolved edit wars.
 The article specifically concerns a rapidly unfolding current event with a definite endpoint.
 The article contains significant close paraphrasing or copyright violations

Another thing to look for is that if the article has been nominated more than once, go back to the previous reviews and make sure suggestions from the other reviews have been addressed.

If the article has any of the above problems, it may be premature to provide a detailed review, in which case you can "quickfail" the nomination in accordance with step two of the GAN guidelines, as long as you explain this clearly on the review page. They most commonly apply when the nominator is inexperienced or is not a regular editor of the article. If you "quick-fail" an article according to the above criteria, leave a short note explaining the major problems and inform the nominator.

Even if an article can be "quick-failed" according to the above criteria, reviewers could also: 

 Leave a short note explaining the major problems, but without officially closing the review until the editors at the article have had a few days to respond to your concerns.  You may find that they are interested in significantly improving the article.
 Provide a detailed review, as more specific information will help future editors improve the article to meet all of the Good article criteria, but close the review as "not listed".
 Withdraw from the review, and let another reviewer decide how to handle it.

Emphasis added by me. So please remember to always actually/carefully read any policies/guidelines before using them (and to not ask other users for opinions, because they might be completely misguided - just always find and read them yourself), like that (source).