to use words effectively, one should not only be concerned with proper grammar, but also take particular care with regard to the explicit and implicit meaning of words. denotation is the explicit dictionary meaning agreed upon by speakers of the language, whereas connotation is the feelings and associations that a word evokes in addition to its dictionary meaning.
as a potential customer, you might question the soundness of judgment of the people using the first sentence to describe a consumer product. the word effective sounds much more desirable and reassuring than the word strong. for a product that is strong could have adverse side effects. also, ingredient is a better choice than drug, even though both refer to the same thing in this case.
a supervisor can "tell the truth" about a subordinate s performance and yet write either a positive or a negative performance appraisal based on the connotations of the words in the appraisal. suppose the subordinate he or she is going to assess has the quality that "never quits in the face of adversity", he or she may have several words at disposal that convey the same denotation: persevering, persistent, tenacious, obstinate, stubborn, and pig-headed. the choice of any one word from the group is simply up to the writer to make, depending on the writer s attitude toward the subordinate as well as on how the writer wants the reader to feel about the person he or she is describing.
words may also connote status. both salesperson and sales representative are nonsexist job title. but the first sounds like a clerk in the store. the second suggests someone selling important product items to corporate customers.