People like to complain about MongoDB. For instance, maybe they feel that it ruined their social network, or any number of other less recent complaints. The debate gets so heated, though, that sometimes valid criticisms - and nothing is above criticism - are dismissed as bandwagon hatred. It's a problem that Slava Kim seems very aware of in this recent blog post on some of the syntactic weirdnesses of MongoDB. It's not bashing, Kim stresses. For developers to effectively use any technology, they need to understand the "sharp edges." Kim goes into detail for each warning, covering five general areas: "Keys order in a hash object" "undefined, null and undefined" "Soft limits, hard limits and no limits" "Special treatment for arrays" "$near geo-location operator" Check out the full article for all the details on what aspects of MongoDB may cause some problems or frustration down the line.