Here’s a practical tip:
Every time you interact with someone, no matter how small the interaction, think to yourself that you will know this person for the next 50 years.
Now, how you treat this person after considering this, is how you should discipline yourself to treat everyone regardless of their position or your current perceived importance of them in your life.
The sales assistant you spoke to a certain way and thought, “ah never going to see them again anyway” – what if after your conversation, this person associated positivity with Muslims, and that sparked his/her interest in Islam.
You may never find out, but you will on the day of judgement when some deeds you thought were important were actually less so and some you didn’t think of were multiplied. Using the example above, what if this same person, became a Muslim, student of knowledge and taught Islam for the rest of his/her life. If your actions were the cause or catalyst, you have a share of the reward.
Focus on the deeds which have the potential to multiply and are a cause of serendipity on that day