It may not seem likely, but something as small as adjusting your seat can have a big impact on your ride. Ensuring that your seat is at the right height will make a difference in how much power you transfer to the pedals, and how much energy you use to move forward.
How you sit on your bike will also affect how comfortable you are, which could affect your enthusiasm level and overall motivation. Not to mention that you can develop injuries if your seat height doesn’t match your body.