In a Walt Disney movie, based very loosely on a famous Copenhagen waterfront statue, Arial wonders what life must be like on land -- perching erect on "legs", constrained to move horizontally on a surface, rather than simply gliding along in any direction wiuth a mere swish of the tail.

She becomes obsessed with strange paraphenalia collected from the surface world, eventually disobeying the command of King Neptune, her father, to avoid all contact with the [evil] forces and people who populate the inhospitable "lands" whose shores constrain her limitless world.

At one point in this cartoon musical, her inquiries lead to a rousing, sometimes raucous, rendition of a song whose lyrics expound and extoll the benefits and freedoms that are unavailable above but taken for granted "Under the Sea". Crustacea, osteichthys, and various other charming aquatic characters sing ... there is ++++++

Unconvinced, Arial pursues her dream and (since this is the Hollywood version) achieves all of her goals and then some, *i.e. handsome prince, loving royal in-laws, a beautiful voice, shapely legs, and so forth) -- destined to live happily ever after after -- but doomed to do so on land.

Romantic +++ aside, it may be instructive to consider what she has given up. However, an objective analysis of her loss may not quite be so easy for creatures who have been conditions as have you an I.

The concept of being underwater tends to make an air-breather uncomfortable. Moreover, the notion of bouyancy in a homogeneous three-dimensional environment can become totally destabilizing for an intelligent, inquisitive, self-aware creature whose underlying, lifelong frame of reference for every experience (real or imagined) has always included such givens as:

Aware of 3D volume

Therefore -> think that if / sea 

Not 2D

Arial, et al -- 3D / sea