Four lettered word.

It can be used when you say goodnight
Or make up after a fight
The word is used in many ways
And the effect can often last for days

It has been frequently used in verse and rhyme
Since the beginning of time
The word caused Adam and Eve to get into strife
Some people even say it is the meaning of life

You are occasionally called absurd
Just for uttering this little word
It is used with a lot of feeling
It can send some people reeling

If a relationship comes to push and shove
Just utter a four lettered word, like love
We must let it be understood
It should only be used for reasons that are good

Don't just use it for personal gain
As it can cause a lot of pain
Not to be used for reasons of lust
With true and heart felt feeling, it is a must.