I've recently noticed an increasingly predictable stream of grossly unsatisfying experiences from people cold calling me to try to get my business. It makes me wonder if great salespeople are a vanishing breed.

Let's face it, doing business with a bad salesperson or vendor representative can be devastating. Missed orders, poor communications, contract violations, bad mouthing, and trade secret breaches are the tip of the iceberg. Moreover, toxic vendors sour the environment for your teammates caught in the noxious wake of the substandard actors on the team.

Let's set the scene. You're prepping for the first meeting. Here's a checklist of warning signals to heed before, during, and after what should be a productive encounter:

1. Dodgy contacts 

A person you don't know contacts an executive in your organization, such as your CEO, via LinkedIn. That salesperson then contacts director-level individuals referencing their exchange with the CEO. "Per my conversation with your CEO Laura Weintraub," they might say.

No matter who this person is or their actual purpose, shady approaches are typically indicative of shady people. Just this week, I saw someone use this approach, making it sound like they were ready to hire us--and it was convincing.

"Per my conversation with Laura, I'm hoping to connect with you regarding a few projects I'm working on specifically with [name and third-party company name redacted]. She is looking to better understand customer data to more accurately target cross device to help optimize ad spend. Aimclear has been highlighted by our Advisory Board as good fit for this project as well as some others we are working on. When is a good time today or tomorrow to briefly connect?" 

It sounds like a very real inquiry to find out more about our services. In reality, this guy was trying to sell me services, not hire my company. Factor that into the toxicity of his approach to get the meeting. Ick.

2. Sketchy business practices 

Ask a potential vendor how they get paid and listen carefully to the answer. An unwillingness to directly address the business model can be a massive red flag portending lack of transparency.

If the salesperson doesn't answer to your satisfaction, try saying this: "There are simple possibilities here. I pay you. You pay me. We pay each other. One of us gets a commission. You're paid on a percentage or a flat rate. Someone marks something up. Please tell me--in very simple terms--what the model is here."

Failure to explain the basic business model and value exchanges disqualify anyone wanting to gain my company's business.

3. Lack of up-front service 

Unwillingness to address questions and concerns early and often is a bad sign. Sales and vendor relationships are predicated on trust and problem solving.

As a customer, I readily admit I can be a handful. I may not want to learn about the "opportunity" to work with you in your exact order optimized for closing me.

I have lots of questions and try to qualify the vendor early, so we don't waste mutual time. I don't want to hear about fancy details, bells and whistles until the basics fit.

If the salesperson is totally rigid and insists on one process, that's a bad sign. Toxic salespeople are unwilling to adapt or empathize, and likely will carry these qualities forward in the relationship. Watch out.

4. Condescension 

Never allow salespeople to make you feel stupid for not taking the bait. Tell a toxic salesperson you're not interested in the model, product, or services--then take note of the closing response.

If the representative tries to make you feel like you'll miss out, or someone else will nab the incredible opportunity set before you today, beware. Toxic people have less empathy and can't put themselves in your shoes.

Great salespeople are along for the journey, empathetic, and supportive--even when it's not a great fit. When you find yourself ready to raise your voice at a salesperson, wish him or her luck and end the conversation. This is a life-sucking person.

What happens early, before, and during your first five minutes with a salesperson reveals a lot about what'll happen later in a potential relationship. A bad sales representative can be an accurate representation of his or her organization.

Ask yourself who your company allows on the street. At my company, team members need to have a lot of experience and be aligned with our values to ever face a customer or prospect.

Use these techniques as a screen--and heed signs that unearth salespeople whose mojo runs counter to the type of vendor you want to do business with.