You mean narcissus from Greek mythology? He felt a lot of pride for his beauty, he was Narcissistic. He cared for no one else but himself and was self absorbed.
I want to buy groceries to be prepared for the week.
The purpose of this sentence is to state the speaker's desire to be prepared for the week by buying groceries. In order to cut out fluffy words, we can take out any extra adverbs or phrases. Also, it is implied that to buy groceries, one would need to go to the store, so this prepositional phrase can also be eliminated if necessary.
Understanding, helpful, nice, fun