The role of the people you call your friends cannot be in any way under/over emphasized in your life, your friends would either do two things that will affect you directly; push us forward or backward, the type of friends you keep can only determine how fast you will reach your set goals, visions and aspirations or how slowly you reach your set goals, vision and aspirations.
I'm learning at this point in my life to categorize the people I find in my life into different friend's zone, there are some friends I can't go to for advice not because they can't advice me but because they don't have enough resources required to give me a good advice. The ability to know your friends capacity as it relates to your life would help you a great deal in clearly defining where they should function in your life.
One of the main reasons why you keep having friends who tend to disappoint you is because you haven't learn to place them in the category they should belong, learn above all to place your friends in the category they belong to; drinking buddy, hangout friends, advisory friends.
Believe me, you would know which friends fit into which category if you take out time to understand them better and how their influence affect you on the long run. Do not go seeking for advice from a friend that is your drinking partner knowing fully well that what you guys share is only those empty bottles on a table.