The things that make others happy may not be the things that make us happy.
As long as the things that make us happy are not overtly selfish, destructive, or harmful, this is perfectly alright.
While being helpful, useful, and generous is necessary if we want to lead meaningful, fulfilling lives, we are not expected to continually sacrifice our happiness for the sake of others.
Self-sacrifice does not have to mean sacrificing that which brings us joy, comfort, and satisfaction for something that does not.
Rather, self sacrifice means giving up our childish, selfish, and short-sighted ways so that we may be more useful to the people around us and the greater purpose of our lives.
We should be able to give of ourselves without giving up our happiness as long as our happiness is rooted in what is actually good for us and others at the same time.
When we find ourselves feeling the urge to do something for others that just does not feel right for us, we should ask ourselves if we are being self-sacrificial or self-destructive.
The former will make our lives infinitely better, but the latter will only make our lives worse.
What we need is a healthy balance between service to others and service to our personal purpose.
We were put here for both, not one or the other.