Simple examples:
* He selfishly kept all the cookies for himself.
* She acted selfishly by not sharing the credit with her team.
* He selfishly chose to prioritize his own comfort over her needs.
More nuanced examples:
* The company's selfish decision to cut benefits affected many employees negatively.
* While it's understandable to feel selfish at times, it's important to consider the impact of our actions on others.
* She selfishly used her position of power to benefit only herself.
Examples using different parts of speech:
* Selfishly, he ignored the pleas for help. (Adverb)
* His selfish behavior made it difficult for him to maintain healthy relationships. (Adjective)
* She made a selfish choice, putting her own desires above the needs of her family. (Adjective)
Remember, "selfish" is often a negative term, so be mindful of the tone you want to convey when using it.