Methods for assembling cabinets of washing machine appliances, and washing machine appliances, are provided. A method includes plastically bending a first side portion and a second side portion of a main cabinet panel relative to a central portion of the main cabinet panel until a first corner is defined between the first side portion and the central portion and a second corner is defined between the second side portion and the central portion, the first corner and the second corner each having a plastic inside angle of greater than or equal to 95 degrees. The method further includes elastically bending the first side portion and the second side portion such that the first corner and the second corner each have an elastic inside angle of less than 95 degrees. The method further includes connecting a rear cabinet panel to the first side portion and the second side portion.