Boasting

Love does not boast. Why? Because boasting is an attempt to make yourself look better in the eyes of whoever is listening and many times, attempts to make those listening feel worse about themselves. This is not loving at all. 

J.R Miller had some thoughts to share about this;
The spirit which prompts a man to talk about himself, however it may be disguised, is really pride and self-conceit; and self conceit is not only a disfiguring blemish in a character; it is also a mark of weakness in a life. 
Its revealing always makes one less strong and influential with one’s fellows. Instead of taking the self-conceited man’s own estimate of himself, people discount it so heavily that they are likely, on account of his self praise--to rate him much below his true value. 
Thus a man's very objective in talking about himself, and proclaiming his own virtues and good deeds--is defeated! He does not receive praise from men--but dislike and depreciation instead!

Let us train ourselves out of the habit of talking about ourselves, and especially praising ourselves before men. Whenever we get the opportunity, let us talk about God and show real interest about the people to whom we are talking.

1Cor 13:4 "Love is patient, love is kind. It does not envy, it does not boast, it is not proud"