DH's employers have been great and really supported him.
It's bonus time and he's got double what he got last year! They've given him fully achieved when last year, when he was working, he just missed one of his targets.
Obviously great for him financially, but he's a bit miffed that he actually worked really hard to get as close as he did last year and this year...
If he's miffed, imagine how you'd feel as a colleague if you knew DH, off all year, had done better than you. Presmuably colleagues will never know, but is this the norm, that people off sick are assumed to have met all targets?
There is potential to do better, if you exceed everything (ie they haven't given him the top bonus) but lots of people don't quite meet all the targets, as DH last year.