That’s the spirit is an affirmation that someone is acting with enthusiasm. 

Three sheets to the wind is uncontrollably drunk.  At sea ropes are known as sheets.  If they are hanging loose instead of controlling a sail they are in the wind.  Graeme Donald’s The Dictionary of Modern Phrase gives a fuller explanation.

Seeing pink elephants is a hallucination resulting from drinking too much alcohol.

Brahms and Liszt is Cockney rhyming slang for intoxicated.  Not much connection with classical music and its composers.

One over the eight is too much to drink.

Half cut is another euphemism for drunk.

Punch drunk might be the result of drinking punch.  Unlike drinks from bottles, there are no labels on home-made concoctions telling the alcohol content.  Punch may be very strong!

Drunk again!  If someone stumbles, this may be the reaction, whether or not they have been drinking.

Gin, gin mother’s ruin is a phrase, which reminds me of an engraving by Hogarth Beer Street and Gin Lane.

Photo Credit Wikipedia

They’re only here for the beer.  It may not be beer in the literal sense.  The people described are light-weight and not really interested in whatever the main reason for the gathering might be, just for the refreshments.  Sometimes people who are there for the “right” reasons make a similar remark as a joke about themselves.

Alcohol is mentioned many times in the Bible.  It is not condemned, but its abuse is.

In Psalm 104:14-15 God is praised for creating wine.  Jesus drank wine and instituted the Eucharist with bread and wine.  But you can have too much of a good thing.

Do not get drunk on wine, which leads to debauchery.  Instead, be filled with the Spirit.  Ephesians 5:18

For anyone who has problems with alcohol I recommend the blog The Bottom of a Bottle.