>If you believe you can, you can, if you believe you can't, you can't.
As a technical individual contributor, what matters is what you can do, not how you feel.
Edit: Yes, yes, all absolute statements are wrong; Attitude does matter some for technical jobs. But what you can do is overwhelmingly more important than your attitude in tech jobs, just like your attitude is overwhelmingly more important in management and sales.
Yes, at interviews, you must act engaged, and you must display what you can do, and that is kind of sales, but it's really easy mode sales.
Sure, I mean, it depends on job role. In sales? yeah, that attitude is required.
(To be clear, even in sales, that attitude is not sufficient. While it is absolutely necessary to project that sort of confidence, that unshakable self-belief, it is not sufficient. You still need to sell. Attitude is sometimes required; it is never enough.)
More specifically to the person you are responding to? when it comes to individual contributor technical roles? As long as you are engaged and interested in the technical questions? It's cool. Having a ridiculous Tony Robins kind of attitude can actually hurt you there; Most technical people don't want to work with a person who's true calling was sales. When I'm interviewing someone like that, every instinct I have is telling me to get them out of the office. I mean, I do my best to overcome my prejudices, and I will still evaluate them on technical merit, but man, it's not easy.
I think that outside of sales and management (note, that's a big part of running a business) defeatist talk and feeling are kinda normal, and unless they are overwhelming for too long, not really a problem.
This is the difference with technical work. What matters is not how you feel or what you project, but what you can do
While getting out from under my business I was super depressed and engaged in a lot of "negative self-talk" in public. And yeah, it probably hurt me on selling that business (I mean, I think I still got a fair deal for what the business was at the time.) but just because I wrote like I was depressed online, as long as I kept going for interviews (and acting engaged during those interviews) I don't think it hurt my prospects as a technical individual contributor much.
I mean, sales is... a different world from technical work. And yeah, I am going to have to come up with a new attitude if I want to go into management ever again But as a technical individual contributor? Ability is key, not attitude.