There's always that little bit more to squeeze out of a Lemon.
When you think there's no more possiblilites available or your up against a challenge, remember there's aways more juice to squeeze out of a lemon.
When your on mile 10 of the great north run, with 3 more to go and your legs are like jelly, your lungs are burning and you consider stopping and your bodies loosing the mind game, remember 'squeezing the lemon' , dig down deep and there will more to come.