I have worked at a small business in my neighborhood for a little over a year now. This job has delivered the most valuable experience I have yet had in my 17 years of using up oxygen, and will carry me farther in the working and living world. I think it’s a good time to reflect on the experience I’ve gained and chronicle the lessons I’ve learned.

The jobs that get overlooked the most easily are often the most important. In my experience, the slightest details can set cascading problems in motion, especially when cleanliness and computers are concerned, so it’s very important to pay attention to everything you do. No task is too small to not be done right. Making careless mistakes will only lead to taking more time later to correct them.

That said, don’t sweat the small stuff. In the grand scheme of things, there are many little things that don’t really matter. Knowing what’s important and what’s irrelevant lets one lead a happy life. Letting miniature slipups roll right off when they don’t really affect anything is a big part of that.

Most people don’t care to make the lives of those around them more difficult, but some simply don’t care. Most people are perfectly pleasant and don’t want to have any adverse effect on anyone else if they can help it. But since this is the world, there are people who want what they want and are willing to be obnoxious (or worse) to get it, and even more who simply can’t be bothered to check how they, or more often their kids, act.

When working in a team, being dependable and trusting are the two most important qualities. If your teammates can’t depend on you to do your job well, they will not want to work with you. If you can’t depend on your teammates to do their jobs well, you will not want to work with them. Mutual trust is the basis of any good partnership, professional or otherwise—but it must be mutual. A house divided cannot stand.

It is essential to be able to be tenacious in the face of difficulty, but it is just as essential to know when you need help and to be able to ask for it. You shouldn’t let problems rattle you, but you shouldn’t press on even if you know full well you have no idea what you’re doing. If you really don’t know, ask for help and ye shall receive. Usually. If you don’t, it’s not your fault, and you should seek greener pastures elsewhere.

45-pound boxes are heavy. I know, I know, this isn’t as pithy as the rest, but when you have to carry several large, heavy boxes down 16 steps, it gets tiring. Especially when the dimensions are such that it’s annoying and uncomfortable to carry them. The effort required to carry 25 gargantuan boxes is substantial, along with the task being very repetitive. Being able to stay sane throughout tasks like that is crucial for being able to do difficult tasks, both physical and mental, in the future.

Variety is the spice of life. It sounds clichéd, but it’s true. Life gets boring when every day is the same. This may not be the same for everyone, but I personally find monotony rather boring. Winter mornings at the shop last year were especially dull. One morning, there were as many sales (three) as people who knocked upwards of 25 greeting cards to the floor. And that was the most exciting thing that happened.

Professionalism isn’t just about not being insufferable. Not being insufferable helps; being at a minimum passably competent, enough so that your coworkers don’t get annoyed, is a must, as is knowing your place as it pertains to authority. Grizzled veterans and bosses are the teachers. Newbies need to be sponges and learn, since they don’t have enough experience to teach with. Being coachable and able to take constructive criticism is second only to being respectful to everyone for the most important component of professionalism.

Life is understood backwards, but lived forwards. However, the lessons of the past are the stars that show the way through the uncharted waters of the future. True professionals don’t drop the act the moment they leave the workplace. Many tenets of professionalism are just as applicable to every other aspect of life, which is why it’s so important to not be intolerable.

Just as integrity is determined by what one does when nobody’s looking, professionalism is determined by how one acts when nobody’s watching.