Marketers rarely think about choosing customers... like a sailor on shore leave, we're not so picky. Huge mistake.
Your customers define what you make, how you make it, where you sell it, what you charge, who you hire and even how you fund your business. If your customer base changes over time but you fail to make changes in the rest of your organization, stress and failure will follow.
Sell to angry cheapskates and your business will reflect that. On the other hand, when you find great customers, they will eagerly co-create with you. They will engage and invent and spread the word.
It takes vision and guts to turn someone down and focus on a different segment, on people who might be more difficult to sell at first, but will lead you where you want to go over time.