The pasuk in Mishlei (15:27) says ??????? ???????? ??????? – One who hates gifts will live.
This is said in a certain context, and not always should you decline a gift. Look it up.
Keep in mind that sometimes by accepting a gift you are allowing the person giving it to get a really good feeling they wouldn’t get otherwise. Also, if your hesitation in accepting gifts is rooted in a dislike of the expectation to show gratitude, then you should force yourself to accept the gifts, and learn to be a grateful person, because this is a not a good trait (I have Gemaras to back me up on and illustrate this point; I’ll elaborate if anyone is interested).