Q:

Sensations that people wanted. Why is it indefinite?

Could someone explain the reason why the definite article is omitted in the first example?

The task was
  clear: pump a healthy dose of emotional appeal into the shriveled-up fruit. Link up sensations that
  people wanted. "Shriveled" and "dried" are not the sensations that most people associate with feeling
  good about their lives.

The author is referring to specific sensations in both cases, not just in the last one, so it should be definite too. Thanks!

A:

The sentence could be understood as either:

Link up some sensations that people wanted.

or

Link up the sensations that people wanted.

If "some" is meant, then it is indefinite and "the" is not needed. The second sentence can be changed to indefinite too while remaining grammatical and without changing its meaning:

"Shriveled" and "dried" are not sensations that most people associate with feeling good about their lives.

Using either indefinite or definite is not a problem in any of these examples.

