If you’re a new company maybe you don’t have any experience with nasty customers, but I’d bet you do have experience with nasty co-workers or contract workers you’ve dealt with in the past. Why not take some time today and list out what it was about them that made you and them incompatible? What about them drained you?
Then think about how to notice those traits so that when you’re meeting with a new potential customer you will have ‘red flag’ moments to alert you that these may not be a good fit for you – no matter the money.
When you avoid the bad customers, you have more energy and better work for your good customers and that in the end will result in more money, promise.
If you already have bad customers, start working on ‘pruning’ them back. One very simple way is to explain you aren’t the best fit to serve them anymore. When appropriate to soften the blow you might refer them to competition better suited to those traits you don’t work well with.
You’ll be happier and that will show in your other work. This may feel counter-intuitive, but it is definitely an important marketing technique.