Happy Boxing Day!

Boxing Day is a holiday traditionally celebrated the weekday or Saturday following Christmas Day, when servants and tradesmen would receive gifts, known as a "Christmas box", from their masters, employers or customers, in the United Kingdom. 

Today, Boxing Day is the bank holiday or public holiday that generally takes place on 26 or 27 December. (from Wikipedia)

The Oxford English Dictionary gives the earliest attestations of the term as being from England in the 1830s, defining it as 'the first week-day after Christmas-day, observed as a holiday on which post-men, errand-boys, and servants of various kinds expect to receive a Christmas-box'.

For hours on end

Four hours on end, for many hours. durant des heures

• We sat and waited in the emergency room for hours on end. 
• The children were happy to play video games for hours on end.

The final/last straw

The last straw (also the straw that breaks the camel's back). le coup de grâce, la goutte qui fait déborder le vase

• Losing my ​job was ​bad enough, but being ​evicted was the ​final straw.
• She's always been ​rude to me, but it was the last straw when she ​started ​insulting my ​mother.