get out of bed on the wrong side

get up on the wrong side of bed

also get out of bed on the wrong side

Meaning

• be very irritable and grouchy
• be in a bad or grumpy mood
• begin the day feeling unhappy and uncomfortable
• have a bad or horrible day from the start

Example Sentences

1. You seem to be in a very bad temper today. Did you get out on the wrong side of the bed?
2. His behavior with everyone is very bad today, it seems he got up on the wrong side of the bed!
3. I think my boss got up on the wrong side of the bed today. He's been awfully grumpy all day.
4. Everything has been going wrong for me today! I think I got up on the wrong side of the bed.
5. Bob seems to have got up on the wrong side of the bed this morning. He has been grouchy and ill tempered all day today.
6. Nothing has been going right for him today. He's definitely got up on the wrong side of the bed.
7. The officer has been shouting at everyone who enters his office today. He surely has got up on the wrong side of the bed this morning.

Origin
The phrase originated in the ancient Roman empire. The Romans had a superstition that the left side of the bed was the wrong side, and getting on the left side, i.e, the wrong side of the bed would bring them bad luck for the day.