People who are in the habit of praising themselves are found everywhere. Such people, no matter how talented are not liked.
Most people do all they can do to avoid the company of such people. Sometimes such people unknowingly hurt others, not directly but indirectly sometimes: so such people become unapproachable.
Sometimes the relations are also spoiled because of the 'I' approach.
The 'I' approach is eventually going to be harmful to such people at the end.
But it doesn't mean that you must underestimate yourself, you should compliment yourself, but don't go on bragging about it all the time.
Words once spoken are indelible and you sure don't want to make a mark that cannot easily be erased.
“PRIDE IS GOOD, BUT PROUD IS NOT”