Daydreams are a more conscious expression of what you are and feel. Dreams you have at night are more subconscious. I often have daydreams like what I would do with a lot of money or if I could do certain things. Sometimes they can prompt me to pray and try to make deals with God.
If a person daydreams about making a lot of money, often it is because they don't make enough money doing what they do or they believe they deserve to make more money. I fall into that category. I believe I deserve to make more money if only my abilities were recognized by the right people and they paid me for my skills.
That leads me to another type of daydream. People daydream about doing something other than what they're doing. This is common for people who do boring jobs. I daydream about writing, composing music, and designing objects that will bring in lots of money for me and maybe even fame.
A variation of daydreaming about doing something different is daydreaming about your job actually being another job. When I mow yards, I sometimes daydream about destroying a microscopic world with a giant machine of destruction. I've daydreamed about this for years. I'm not mowing a yard. I'm destroying a continent and the people have to flee before the machine destroying their land comes back to destroy more. It makes the time seem to pass faster or at least I have a fantasy goal; destroy a world.
A popular daydream is the one about being a celebrity. You might pretend you're a famous basketball player playing hoops or a slugger when you're in the batting cage. When you're on the driving range you may daydream about hitting a ball as far as Tiger Woods does. This is generally harmless. But it can be frustrating if you know that no matter how much you practice, you'll never be as good as the person you daydream about.
People who are bored daydream. People who want more out of life daydream. People who believe they are worth more than they are paid or they have abilities they don't think are being recognized daydream. Daydreaming too much can interfere with your job. Yet some occupations almost require people to daydream. Writers and composers can construct stories and music from the daydreams they ponder. I sometimes wish I had a small recorder with me to record what I hum. I might have over 120 hours of music if I did.
A little daydreaming is healthy. A lot of daydreaming may cost you your job. Weird daydreams reflect on your mental condition. As long as you can control the amount of daydreaming you do and when you do it, it is fine. Just make sure it's more like a mental treat instead of a troubling and at times frustrating diversion.