Tirmidhi

Benefits and Issues:
Benefit: This is the instruction of the Messenger of Allah (sallallahu alayhi wa sallam).
One should also, as much as possible, drink water while sitting.
This is a discouragement of a non-obligatory (tanzihi) nature.
And without any valid reason, drinking while standing is in no way appropriate.
Several hadiths have been narrated on this subject.
If all of them are taken into consideration,
it becomes clear that Islam encourages drinking while sitting in comfort.
And this was also the regular practice of the Messenger of Allah (sallallahu alayhi wa sallam).
However, if there is a need, then drinking while standing is also permissible,
as is made clear from the next narration.
But it cannot be made into a regular habit.

Benefits and Issues:
Some scholars have interpreted the prohibition as indicating dislike (karahah).
That is, it is better to drink while sitting.
Some have considered drinking while standing as something specific to the Messenger of Allah (sallallahu alayhi wa sallam), meaning it was permissible for the Noble Prophet (sallallahu alayhi wa sallam).
We should act upon the hadith of prohibition; caution lies in avoiding drinking while standing.