From the time we are young, we are told that there are some traits that you never ever want to exhibit and that's that. Like many things in life, though, there are pros and cons to the "good" and "bad" traits. This largely depends on the situation and what the results of the trait yield as an outcome.
For instance, being selfish when it means putting your own well-being first is healthy and not always an easy decision in life. When you're an overly caring or sensitive person, it can be especially hard to not want to do everything humanly possible to help those around you. While you might enjoy being known as the person that is so selfless that they never ask of others for something you need, this is harmful to yourself later down the road.
It might be something that can be taken for granted to be able to ask others for what you need. Being able to make sure your own needs are taken care of before you see to helping others can be a skill that not everyone prioritizes in life. But think of it this way: if you need to be there to take of others and make sure something happens properly, you have to make sure you've given yourself the time you need and the resources whether it be food, tools, etc., in order to be the best you possible. If you were to give away everything you needed to go about your routine healthily, then you would be running on fumes either physically, mentally, emotionally, or sometimes a combination of all three.
The key is to know the difference between necessary selfish actions and harmful selfish actions. When being selfish means putting your feelings first because you will feel healthier emotionally, or just making sure you've eaten before giving your food away to someone else, then these are important and necessary moments in which you need to value where you're at and put yourself first. This is extremely different from being self-involved because you don't want to think about others ever.
With this in mind, it's important to be aware of what you need in life when faced with situations either big or small. It's important to help others around you, it's wonderful actually, but there is importance and necessity in taking care of yourself so that you are able to make a difference helping others.