They say you can't have everything? If I want a new mountain bike or a sleeping bag I can just save up and buy it. If I want to go on a trip I can plan for it and go. If I want to quit my job and dirtbag it I could work until retirement and then go for it. In fact I can't think of many things that a normal person would want to do that they couldn't do with some preparation.
Maybe what they should have said is that you can't have everything at once. Better yet, you can have everything. You just have to plan, save, and be patient for the right time to have it. Now if I could just figure out who "they" are.