Some of these people start dreading Mondays on Sunday. They "pre-order" dread or borrow worry from the futurel.
For some people, those who don't like what they are doing, Mondays really are something to dread. Perhaps it's the job they took to just pay the bills while they go to school. Or maybe they were out of work and took something; anything to feed their kids.
There are other people though, that in the same situation, make the best of it and make it better. They end up making their day better because they invest in it. It may be that they "may as well make the best of it" or it may be that they have a calling.
Remember though, Mondays are different from the weekends; not better or worse; different . . and don't need to be dreaded.
If you're a Monday dreader, take a minute to think of your worst Monday for the last year. Barring catastrophe, did they end up being so very terrible? Was more that 50% of the day so bad that it spoiled the whole day? Was it worth feeding into the dread?
What if you spent that same amount of dread energy looking at the good things about Monday? What if you spent some energy making Monday better for yourself and the people around you?
I'll bet you'd make today a good day.