I found an article on something called thoughtforms. In the article it did not actually say what a thoughtform is. However in one part they claim that they can make a person feel a certain emotion using one, but I've always been under the impression that you cannot make anyone feel an emotion or have a belief through magick. I'm really confused, honestly. Any information would be appreciated!
Well... a thoughtform is, simply put, your thoughts given a sort of self-contained form. We usually refer to the energy however you might think of it as focusing the intent for your thoughts to carry a little will of their own which directly reflects your will. It doesn't usually last long, but it can be a fun tool.
As for the capability, any number of things could influence someone's feelings- there is evidence to suggest that even the color shirt someone wears can do so. And your thoughts naturally do influence your feelings. If a sensitive person came into contact with someone elses thoughts, this could effect how they feel via a subconscious reaction.
Have you heard of Empaths? Everyone has a little bit of empathic potential, in my opinion. Because it is part of the way humans naturally are, to be sensitive to each other. So it is possible for your feelings to be influenced by outside sources.
Naturally, if you don't want to be influenced, there are ways to center into yourself and ground excess spiritual energy, especially that which is recieved from outside of yourself.
Also, many spiritual practitioners consider cleansing yourself spiritually to be a very important practice because of all of the negativity that you can 'pick up' throughout your days. So it is almost like taking a spiritual bath to keep yourself clean and hygienic.