You obviously have never dealt with too many customs officers have you?
Whenever I have dealt with ANY customs agents, they rarely smile or show emotion. They ask you many questions, and often ask you the same question in different ways to see if you are giving them the same answer all the time, or lying to them.
First, you should NOT take it personally. This is done for your own safety. Think of it this way...If they do their job right, they may catch criminals like murderers, terrorists, and smugglers from trying to get out of the USA. The same as US customs is trying to stop them from ever getting INTO the States.
Second, always give the agents a straight honest answer. If they ask you where you are going, you just have to say the city. If they ask why, it's to find out if you will be trying to work illegally in Canada, so they want to make sure you are on vacation or if you are working that you have the right paperwork to do so.
Third, you are not entitled to come into Canada. It is a privilege to enter another country. It's like going to a neighbor's house and knocking on the door. When they answer, you say "Can I come in?" but what if they don't want you over that day? Is your neighbor required to let you into their home? No. If you try to force your way in, they call the cops or shoot you. If you argue with them and get into a fight at the door, odds are you won't be invited back in ever again.
As for the officers being rude and mean, I have never seen that. I did have a US border agent get a little testy with me and ask me several questions because he thought I was going down to USA to work, saying he did not want me to "steal any jobs from Americans".
You can get jerks working at any place that are given a little power and like to use it. But if you are polite and respectful, not arrogant and confrontational, you generally get through no problem.
But if you don't like Canada's agents, you should try South Africa. In Capetown, I had two guards in the security area holding automatic weapons aimed towards me as I was coming in. I had to press a button and if the light turns green, I go through no problem. If it turned red, I would be escorted under armed guard to a security checkpoint for a more detailed inspection and screening process.
Nicest agents I've encountered: Derby Line, VT
Worst agents I've heard about: Detroit-Windsor