When you start a store, you're looking for any angle to make a buck. Any extra income will keep the lights on or preserve your savings. This is a good attitude to have, but eventually you begin to see the outlines of your business, a view of what belongs. A sculptor, I've read, has a vision for what their piece will eventually look like and they remove everything not that. A business is also like this, although customers will help form that vision.
Not taking every opportunity sounds like heresy. It sounds like you're giving money back, the most hated thing in retail. What you're doing is honing your vision, crafting your art. A well focused store with a clear vision will make more money than a looney tunes, anything goes store. A counter intuitive analogy is crowded shelves. If you can highlight one thing on a crowded shelf, and you pick the right thing, that item will likely sell better. You may need to have less stock on that shelf. That's right, less inventory will make more money in some circumstances. A store is like this overall. A store needs coherency, flow.
It's not just inventory, you need to set a tone. If you're going to have an upmarket store, you don't need downmarket product and services. I used to sell used video games. It made me some money, but it harmed the up market tone of the store with a lot of muggles who could care less about my offerings, other than their ability to dump the latest Madden game. It was gross.
My tone is set by my staff primarily, then the surroundings like furniture, fixtures, and even flooring. Music sets or ruins a tone. The inventory is a tone setter, including what I carry, where I place it, the depth and breadth of stock. The walls are decorated, in a perfect world I have nice displays and demo tables. I agonized over our unfinished ceilings. Oh, it's all the rage in Portland! I am not from Portland. In the end, I took a few months of free rent, in exchange for unfinished ceilings, and decided not to look up for a while until it grew on me.
I can't tell you what your tone is, or what's good or what's bad for you. You'll have to figure that out. You might name your store after a farm animal and sell at a deep discount, making it up in volume through desperate marketing and attention seeking. You do you. You might also need every angle to survive, especially in a small market. The smaller your market, the more angles you'll need or want.
Imagine a store in a market so huge you could specialize in something tiny, like only selling role playing games. I dream of a megalopolis where I can have a corner store only selling the games I care about. That will never happen, you're thinking, but I can point to a lot of things I don't do, that you might consider essential, because it's simply an unnecessary pain in my ass. Maybe my competitor will notice and start doing it (this has already happened). Such is business.
Have a vision of your sculpture in your mind. Remove everything that is not that. "Consider Yes" is a great RPG mantra to enhance player agency, but "Ponder No" may be appropriate for a maturing store with a clear focus. As you sculpt your store into existence, move slowly enough so you don't lop off an ear or make the lips too thin. It's hard to go back. Accentuate what's working. Don't look at the other artists with envy because they're sculpting something cool that's not part of your vision. I do this all the time. If you don't have a vision, why did you even start? Maybe spend some time in contemplation, thinking about what you really want to be doing with your store. The customers have spoken, have you? Remove everything not your vision.