You have two options to bring on your next adventure - a big backpack or a small backpack.
The big backpack holds everything you could possibly need: things you've been carrying around out of comfort, new things you've picked up, and things kept out of the fear of a surprise along the way. The weight of choosing the big backpack, full of possessions, will cause fatigue. Although you've filled the big backpack, it is unlikely you will need every thing. Choosing to carry more will drain your energy and will not have a positive effect on your adventure.
Instead, choose the small backpack. You'll need to consider the value and purpose of each thing before adding it. Even though you will not have packed for everything that could happen, you'll be more confident with the fewer things you're carrying. The lightness of the small backpack will leave you with more energy to face what ever comes your way.
Carrying less weight benefits you in the end.