I work closely with my boss and we often need to talk about solutions or how we want to implement our products.
Every now and then, we have a disagreement and he gets (a little) mad at me. I always avoid having an argument with him and do what he thinks is good.
Anyway, I want to be calm and more assertive in that type of situation. I want to stand by my point and convince him to follow my idea.
Is it a good idea to do that? If so, how can I do it?
If all he has to do his show a little anger and you'll give up, there is no point in having a professional opinion. Don't go out of your way to upset him, but do not shy away from giving your input. A good salesperson will ask for a higher fee at the risk of upsetting a client. It is difficult to negotiate from a position of fear.
Not getting upset yourself may take some practice. I've been at places where the loudest voice in the room got the most attention, so I played along willingly. That's just me. Take some pride in keeping calm and not conceding your position. Ultimately, you make suggestions and your boss makes the decisions. Offer all the information, arguments, things to consider, etc. and then ask him what does he want to do? Calmly accept the decision and start doing what it takes to make it work.
They said people jump in because of the company, and they leave (or stay) because of the boss. :)
First, discussing with your boss is not necessarily bad, and depending on culture it could be more/less tolerated. (e.g. I've met corporations where you're not supposed to talk to your manager unless she talks to you first).
That said, depending on the kind of job and on your seniority/experience (e.g. First Violin on an orchestra vs apprentice on a workshop):
Some more general advice you could take advantage of:
One approach is to direct the conversation back to an investigation of the problem.
Firstly, you should acknowledge that there's a disagreement, and propose to change gears to break the stalemate. You've both made your cases and you still don't agree on what should be done. Defuse the situation by saying something like: You're the boss. Ultimately, what you say goes. But I don't think you want to force every decision we make. Let's see if we can get somewhere by changing perspectives.
(Ideally, he should be the one to lead the discussion this we, but we don't always get the boss we deserve).
The trick is to get away from solutions. When you talk about which solution to choose, you end up arguing, because solutions are mutually exclusive. When you talk about aspects of the problem, you can both be looking out for different aspects of the problems and still have a productive discussion.
For instance, your boss will likely want a cheap and fast solution, whereas you may want one that is maintainable, and works well for the customer. The solution is to map out what these requirements mean in detail and to find a smart way of satisfying all of them. You might, for instance, design an ideal solution, but then add a plan of implementation that allows for the first implementation to be delivered quickly and cheaply, but with a continued development towards a more sustainable solution.
A second point to bear in mind is that once people are convinced of something, reason and logic work against you. The more arguments you throw at them, the more they dig their heels in. The trick is togive up on convincing them of the whole big truth at once, and to find somesmall commitment they can make. Ie. don't try to convince someone that Apple is better than Microsoft, buy them an ipod nano. Break the absolutes. Don't try to turn a staunch Republican into a Democrat, just ask him which Democrat he'd support if he had to. Find one small commitment towards your point of view and ask them to make it (and be prepared to do the same).
