Do you invest any money? Do you invest all of it in the company you work for?

Why? The work you do in your spare time can directly (by reusing libraries you build) or indirectly (learning a new language, framework, etc) improve your performance at work.

Only reason you should ever feel guilty is if your side projects are meant to directly compete with the work you do at work. In that case, I would say it's a bit unethical.

I assume it's because he/she is spending time doing the side projects, time which could instead be spent doing whatever he does for his job.

I feel like this is actually one of the things I really hate about being paid salary. I either feel guilty for not working enough or just hate not being able to spend time doing other things.

Don't you think that companies should support such personal deeds? This is very common in the electronics community, where expensive instruments are needed and workers find it difficult to buy them themselves. Eventually, motivated and eager-to-keep-learning employees are the best assets that a company can have.

does your company feel the same way about u?

I promise you that your company doesn't feel the same about you (or any of your coworkers, for that matter). When it comes to employment, loyalty died out many years ago.