Back when I was first getting deeper into energy work and awareness, a psychic I worked with told me that my nature was more to merge, and that for me, generating a shield of light wouldn´t be effective. She recommended strengthening my own energy, and ways to keep my aura cohesive, so I could merge with people and places, while maintaining my own energy, and not be negatively affected by the process. This has worked well for me, along with using stones like black tourmline to repel negative energy. When I´m in situations where I feel negative energy from people and places as unpleasant, invasive, or unwanted, I have a variety of mantras, practices, and ways to dispel or transform it. IMO, using a bubble of light or personal energy shield can be effective for some people and situations, but won´t work for everyone. I also like things to be easy and require less personal effort, so carrying a piece of black toumaline in my pocket is much less work than having to construct and maintain an energetic shield. It´s also very useful when your own energy is down, due to stress, colds, etc.