Canada has several fault lines, although Canadian political culture in general is much more accommodating than American political culture.
The two big fault lines are Quebec, and Western Canada.
Quebec has a different linguistic and legal system than the Rest of Canada, and for decades enjoyed special privileges from the political class due to the fact that any political party needed to hav a majority of seats in Quebec to have a chance of forming a majority government in Parliament. (This condition no longer applies as Canada's demographics and Parliamentary seat count shifted west. Governments since 2006 can now win a majority without winning Quebec). the political class of Quebec has stroked grievances and demanded special privileges for decades and the rest of Canada has acquiesced in order to preserve Confederation (and more crassly, to ensure that political parties could be elected).
Now that Quebec no longer has that special status of being needed to win elections, political parties can spread their capital and vote buying pork to other regions of the nation. The Quebec separatist movement could use this to finally create enough feeling of resentment to win a referendum for separation, although this would be a Pyrrhic victory at best, as parts of the province would then separate from the new "nation" to rejoin Canada. The northern part of Quebec is home of the Cree people, who are not at all interested in separation (and sit on a treasure trove of mineral and hydro wealth), the Eastern townships and a large part of the City of Montreal would also make a break for it. Quebec could be embroiled in a civil war while Canada sits on its hands and watches for the dust to settle.
Western Canada (Manitoba, Saskatchewan, Alberta and BC), although not homogenous, are also generally resentful of being exploited by Eastern Canada for their mineral and agricultural wealth, without a corresponding say in Parliament. This also has changed over time, but even in the late 1980's, the populist "Reform Party" gained a huge following not for advocating separation, but with the slogan "The West wants in". Western Canadians bear the brunt of paying lots of taxes for the benefit (they see) of Eastern Canadians and particularly Quebec, and not getting a lot in return for the money. Now that demographic and economic power is building in the west, the idea of Western Separatism (always fairly tenuous at best) may be fading, but the last ditch attempt by the so called Laurentian Elites to turn back the clock under the new (2015) Liberal government might stroke resentments again, and certainly lead to much more rancour as Westerners see themselves being screwed again.
So Canada has two potential flash points, and they are actually interrelated. A particularly clumsy government (one not truly ready to govern) could end up firing up both the Quebec and Western separatists, one side demanding more handouts while the other side demanding more control over their own money and resources.