A short story about doing the right thing

'Come on, Anna – get a move on. There's another lap to do yet!'
'It's no good Bethany, I can't.'

Anna and Bethany had just finished one circuit of the playing field, and Anna had had enough.

'I know it's the fun-run on Saturday' she said. 'But I can't run for two miles and that's that. I'm going to drop out.'
'But what about all your sponsors? You can't let them down!'
'Well I can't do it, and that's all there is to it.'