Margarine was still relatively new in the 70’s & early 80s and most of the ads focussed on its health benefits. The category was generally seen as negatively motivated with people buying margarine to avoid the perceived health risks of butter. So much of the advertising was plain annoying (eg Ripper Rita).  Mojo took a totally different slant with Meadow Lea and linked it to a positive motivation of reward.  They came up with the line “you outa be congratulated” because they wanted something which rhymed with polyunsaturated – not something easy to achieve.