Keep in mind that friends (especially of the the younger years) come and go, as yic pointed out. Invest in the lasting relationships before the temporary ones. Another thing to realize is that while it is a lot of fun to advise people, few people really put themselves through it enough to feel the responsibility of their advice.
Chazal say that if you can give advice like Achisofel then give it, otherwise don’t. Achisofel advised Avshalom not to wait overnight to chase Dovid. Avshalom didn’t listen. Achisofel, knowing that his own advice was perfect, understood that Dovid will have a chance to gain a standing. Therefore, he hanged himself in fear of Dovid’s wrath.
I find that most, and especially young, people throw advice based on their current mood or whim. A family treats the issue differently.