All vendors lie, some vendors lie compulsively. If certain vendors told me the sky was blue I would go out and check.

Ah, another tip. Learn the phrase "it is what it is". It's the answer to everything from lieing vendors to incredibly poor implementations. If you can learnt to accept bad software, implement it in a way it's not going to break the bank to support and move on, you'll find yourself avoiding the path to the "grumpy SA".