The conservative party have done terribly, terribly, for our population and economy 
Child poverty has risen significantly, a's has food bank use. Cuts to education and NHS are significant, even if they claim to "protect the budget" (I. e. not cut but not increase so it falls behind with inflation and in real terms is less).
They have cut welfare and disability benefits for the people who rely on support the most, and the reason so many rely on tax credits and housing benefit is because it is impossible for many to buy a home (you don't get housing benefit if you are a home owner) and private rent has no regulation and is extortionate in densely populated parts of the country.
They only called the election in the the first place to avoid an election fraud scandal FFS 