If you are, this is the sort of thing you may face time after time!
Guy turns up at base 45 minutes ago, starts to prep van for tomorrow?
Me - "Hi there, why are you back so early?" (Knew he had at least 7 hours work on today)
Him - "It rained"....he's right it did, but as he drew up so the sun came out again and anyway we work in the rain and he has done so with no problem before!
Me - "Ok, but it has stopped now, so please go and finish the worksheet"
Him - big sigh, but...but...if...if...
Me- " yes?"
Him - "I am wet to the skin"
Me - "Why? your waterproofs that we supply for you are in the van?
Him- "I find them awkward to work in (no-one else does) so I didn't wear them"
Me - "Well that was your choice not to and the workload should not suffer because of that, so please go and finish the workload.
Him - " I'll do it tomorrow"
Me- "No tomorrow is already fully scheduled as is the rest of the week"
My thoughts - now hang on mate I decide on the scheduling not you!!! 
He has gone back out now after sighing, puffing and groaning, but reading between the lines, he really did not want to work today and was trying it on. As soon as I quickly calculated the deductions if he didn't go back out and told him, he went like a shot.
Could do without this sort of aggro, but that is the life of an employer

Warning bells, he will probably call in sick 2morrow!