Motivation, like carelessness is contagious.
To give some back story, I'm a Line Cook at a semi-popular family run Italian restaurant in rural Pennsylvania. There is only about 3-4 of us working at any given time. That includes, a manager, a server, and if we're expected to be busy that night, we'll have an extra floater to help wherever needed. The floater is typically the restaurant owner's son.
Now that you have some background information, let me get into why all of this is relevant. To get straight to the point. The owner's son, let's call him "Frank", is one of the most pessimistic and slothful people that I have ever met. Not to say that "Frank" isn't a good guy. He's just the type of person who is unhelpful whenever he is needed, and has some sort of deep seeded resentment towards being a hard worker. You can typically find "Frank" sitting at a corner table playing with his phone.
Most of the staff that we have are relatively young and tend to look up to "Frank" as a figure of authority, this is particularly damaging because they see him squandering his time away and emulate his attitude. Whenever that happens it usually brings down the overall productivity of the entire restaurant. I've noticed this lack of willingness to work, and work hard, has consistently happened whenever "Frank" has showed up to work that day. Be it in the first shift, or second. The attitudes last throughout the day.
How I try to remedy the situation
To the people who know me, I'm a very positive person, with a willingness to work hard and prove my worth. These are some of the personality traits that most successful people have, and to good effect. Whenever I'm exposed to anyone with a negative attitude, or someone who has some of "Frank's" personality traits, I do my best to try to capture their interest and get them excited about doing whatever task or project they may be doing by making it fun. You could turn it into a game or just add a bit of humor into the equation. Usually, that will help lift the spirits of the negative person but, if nothing you try works, avoid the negative person like a plague. It may seem a bit harsh but, trust me, just like motivation, carelessness is contagious.
Also, when avoiding the person. You have the chance to outshine them, and look good to your superiors. This can benefit you actually, and the people around you will want to emulate YOUR success.
In short, try to help the "Frank"s of the world, but if nothing in their attitude changes... Avoid, Avoid, Avoid. And try your hardest at everything that you do.