Simple. I love simple things in this life, and keeping my camera bag simple is a part of that simple philosophy. A few months ago I sold two lenses as they were really just duplicates to some degree. Consider the 18-55mm lens, a staple in my bag and probably most everyone else? It’s small and very versatile in it’s focal length.
The 70-300mm zoom is another workhorse in my bag, it works great for close-in photos too if done correctly. Then there’s the 18-20mm Sigma wide-angle lens. As with the other two lenses, they are like people. Each different with different capabilities. It takes time to learn each lens and it’s peculiarities and capabilities.
Selling those two lenses both simplified my camera bag and strengthened it as well if you take my meaning.