One of the most troubling consequences of falling in love too fast is losing who you are in the process. Although some relationships happen very fast and are totally meant to be, some are forced, and sometimes people who are not equally yoked spiritually make a strong attempt to change themselves in hopes that these changes will help to solidify their relationships. I strongly discourage this type of change because the usual end result is a person not being happy in their relationship & at some point down the road resentment sneaks right on in like a thief in the night.
We must all remember, the way we start a relationship is the way we must continue on in that relationship for it to work. One way to ensure you never face this in your relationships is to always be true to who you are. Show your significant other from the start the things in life that you really care about, your true interest & desires, if they really love you they will also take interest in those things and encourage you to be that person instead of someone you are not.