Verb
wake up on the wrong side of bed (third-person singular simple present wakes up on the wrong side of bed, present participle waking up on the wrong side of bed, simple past woke up on the wrong side of bed, past participle woken up on the wrong side of bed)
(idiomatic) To feel grumpy and irritable; to be easily annoyed.
He can't stop shouting at me: he must have woken up on the wrong side of bed this morning.