Let's end this right here and now: most recruiters / hiring managers don't really care what your hobbies are - or at least not most hobbies. When I'm trying to hire someone, I'm looking for three things: (1) intelligence (2) coding skills (3) good personality (4) work ethic. #3 is really only prioritized in a small company situation and #4 is really hard to determine.
On your resume, I want you to prove to me that you are smart and that you can code. And maybe that you have a personality that I'd want to work with. The fact that you play tennis rarely relates to any of these.
There are a few exceptions to the "No Hobbies" rule:
- Your hobby is a major accomplishment. For example, you completed a marathon. That might just barely show a relevant work ethic, and might just barely be worth it to add.
- Your hobby is tech related. For example, if you write a blog about technology - yeah, I might care about that. It improves your coding skills since you'll have a better knowledge of what's going on with technology.
- Your hobby shows a good personality. For example, you are part of a stand-up comedy troupe. You probably have strong communication skills and a good personality. It won't matter at all for getting hired (I'll evaluate you based on my own interaction with you), but it might help tip you over the edge as far as selecting your resume.
- Your hobby shows leadership. If you're the president of a club - or, better yet, founded a club - that might get at work ethic.
The vast majority of the time, your hobbies are none of these things. They're merely some vague item like "traveling" or "tennis." I've played tennis and thought it was fun - can I list that on a resume? I recently saw a resume (from an Indian guy) that listed "Traveling: extensive traveling over North and South India." This is sort of like saying that I love traveling and I've traveling all over the US. That's not really what we call "traveling."
The problem with hobbies, other than them just being totally irrelevant, is that anybody can list the same hobbies. They're rarely ever backed up with evidence, making them even more useless than they were to begin with.
Many students, when I tell them to cut the hobbies from their resume, tell me about how in one interview they / their friend was asked about one of their hobbies. That's probably true - I'm sure there are lots of interviewers who periodically ask about hobbies. But, I have a whole lot more stories about being asked about your projects, work experience, etc.
Remember: every line on your resume is replacing something else that could have gone on your resume. You should add the line that contributes the most value. Your hobbies rarely do.