But if the tenants are being a pain now we are wondering what will happen if we close the deal.

If you're dealing with motivated sellers, there's no issue with letting them know you're an investor as long as you don't come off as some shark who is just trying to get the house for the absolute lowest cost, but instead you look for their pain point and try to really solve their problem.

Working with banks for financing can be a real pain.

It is a pain when they don't show. 

Have them sign an agreement with the tenants on your lease, make sure it states when they are moving in, who is moving out, and how they are handling the deposit.Sometimes, the change over of tenants is easy, sometimes it is a pain, it depends on how difficult they make it. 

Would you expect your doctor to remove your appendix without doing further testing just because that's what usually causes pain in the lower abdomen?

Now that is a 2 way street as the seller would like to get the buyer (pregnant) on the deal meaning have a lot of legal expenses,report costs paid for,etc. so that it is painful for the buyer to back out.I usually have a clause that due diligence does not start until ALL items are received from the seller.

What's your biggest problem/pain point?

They made me board up a single pain window in the basement and put in a low flow shower head.

This was a great rental and was paining itself off nicely until this happened.