Wikipedia:Opening up a can of worms
|This essay contains the advice or opinions of one or more Wikipedia contributors. Essays are not Wikipedia policies or guidelines. Some essays represent widespread norms; others only represent minority viewpoints.|
|This page in a nutshell: Doing something drastic can be good, but make sure you're ready to accept the consequences.|
If you 'open a can of worms', you [often unexpectedly] set in motion or discover something that has wide-reaching consequences. This sometimes happens on Wikipedia, and nearly always leads to massive fluctuations in the community or policy.
There are occasional bad faith AfD nominations on Wikipedia, and there are some rewrites which may cause havoc with other users. There are also more mild cases of these that can actually change the way Wikipedians look at things, sometimes for the better. If you want to change something that's potentially a staple part of the community in some people's minds, then you can certainly do it, just keep in mind that it could cause some serious ramifications, hence the term, can of worms.
The biggest example of the can of worms is most likely Wikipedia:Miscellany for deletion/Wikipedia:Esperanza. When User:Dev920 nominated this for deletion, there was no way of knowing if she would have been attacked by many or praised. This is an example of the benefits of opening the can of worms properly. She ended up being mostly praised.
Conversely, attempting to open up the can of worms in some cases does not work, such as in the case of Wikipedia:User_categories_for_discussion#Category:User_en. If that category were to have been deleted or renamed, then hundreds of others would have to follow suit. User:Twp opened it up, yet was met with mostly disagreement. This in itself is not bad, as opening up a can of worms unsuccessfully can help reiterate both policy and general consensus within the Wikipedia community.