A lot of the differences exist because the US broke away from Britain in 1776. Practices diverged from there. In some cases, the US practice is actually older and less evolved than current British practice.
In Canada, we sort of broke away from Britain about 100 years later. From then on, in Canada, the influences of Britain and the US tended to compete.
As an example, in Canada, we drink our mass-market (i.e. not craft brewed) beer cold, but it actually has flavour.