Do you jump out of bed every morning with a spring in your step?
Or is it your partner who is first with a seize the day mentality that you just can't stand?
Well, research now suggests that when it comes to waking up on the wrong side of the bed, it is all about which side you have slept on.
A study by sleep experts at Sealy UK found that those who kip on the right-hand side of the mattress are far more pessimistic than those who doze on the left.
They are also more likely to hate work, which adds to an increase in grumpiness every morning.
Sleeping on the left-hand side of the bed has proven to be 10 per cent more likely to give you a positive outlook on life, providing an 8 per cent surge in how likely it is you will love your job.
Neil Robinson, Sealy's top snooze analyst, said: "The research certainly highlights an interesting trend " could it be possible that the left side of bed is the 'right' side?
"For many co-habiting couples this may prove problematic " with each side of the bed a fiercely guarded territory, changing from right to left may not be that easy."
In probing the sleeping patterns of 1000 adults, the research found loners who prefer their own company prefer sleeping on the right and those with a large circle of friends plump for the left.
It also found that some couples never have to cross that bridge " as one in three head to separate beds every night.
Half those who usually share a bed head for the spare room to escape their other half's snoring and a quarter to get away from their restlessness.
One in ten are pushed out by their child or pet.