In that spirit, I will call attention to your first sentence, specifically the comma. In my opinion, that can be improved. One of three other constructions would be more appropriate:

• I am really happy when people are quite strict in code reviews. It makes me feel safer and I get to learn more.
• I am really happy when people are quite strict in code reviews, because it makes me feel safer and I get to learn more.
• I am really happy when people are quite strict in code reviews; it makes me feel safer and I get to learn more.

The first of my suggested changes is favoured by those who follow the school of thought that argues that written sentences should be kept short and uncomplicated to make processing easier for those less fluent. To me, it sounds choppy or that you’ve omitted someone asking “Why?” after the first sentence.

Personally, I prefer the middle one, because it is the full expression of a complete state of mind. You have a feeling and a reason for that feeling. There is a sense in which they are inseparable, so not splitting them up seems like a good idea. The “because” explicitly links the feeling and reason.

The semicolon construction was favoured by my grade school teachers in the 1960s, but, as with the first suggestion, it just feels choppy. I tend to overuse semicolons, so I try to go back and either replace them with periods or restructure the sentences to eliminate them. In this particular case, I think the semicolon is preferable to both comma and period, but still inferior to the “because” construction.

I’ve clearly spent too much time hashing stuff out in writers’ groups. :)