BC provides excellent examples of the distortions of the single-member plurality electoral system (also known as first past the post).  The system does a poor job in translating a party's overall share of the votes into a proportional share of the seats.

For example in the 1986, 1991, and 1996 elections, the NDP share of the vote was steady at roughly 40%. However, it formed the opposition in 1986 but the government in 1991 and 1996. And, in 1996, it actually finished second behind the Liberals in terms of overall share of the vote!

2001 provides another example of representational distortions due to the electoral system.  The Liberals won about 58% of the votes and swept all but 2 of the seats. Even though the NDP and Green Party received double-digit votes shares, only the NDP won any seats.