Sometimes, I see someone who takes on a necessary burden. Not all burdens are "too much". Sometimes, we choose to take them on willingly and - though we feel the burden - we also feel we are doing something good. When we are preparing important exams, or are in the final stretch towards a deadline, or when we are caring for someone who needs a lot of help, out of love.
In other words, not all burdens are equal, nor are all those who take them on equal. We can take some burdens on cheerfully, with love, or because they mean something to us - a better job in the offing, the conclusion of a successful project, the chance to win a competition; or simply, showing love in a way that is needed. In fact, we might not even view them as burdens, though undoubtedly they weigh on us, in absolute terms, and close other avenues as long as we are burdened in that way. For instance, you might be caring for your sick mother and not be able to go out much. But if you choose to do it, do it cheerfully out of love - then who is to say you have tunnel vision, can't let go, are a square and all these negative judgments heaped onto that poor guy who is already carrying so much!