There is nothing that can make me turn away from *UNIX system.
My preferred technologies are the ones that i don't know, especially if related on BE system/microservices and, of course, they run on top of Linux sys.
If these three things are not linked during my "workday" i can't be as useful as i want to be.

Golang:
- MongoDB, Redis, cgo, call to custom C function, high performance webservices (fasthttp)
- Fast file parsing (C interoperability)

C, C++:
- Cryptocurrencies enthusiast
- Apache webserver
- Configuration, tunining, security (SSL security, CVE mitigation), custom C module (plugin)

Python, Java:
- Neural Network, Classifier, Clustering: scikit-learn
- Micro services
- No-sql database (Redis-server,MongoDB,Cloudant)
- NLP (natarual language processing): spaCy, nltk
- Image Processing: dlib, opencv, face_recognition, skimage

Shell:
- Extreme automation of *UNIX environment.
- Installation script: automatically download, compile and install from source for best performances

Security & SysAdmin:
- Linux system hardening & tuning (firewall-cmd,iptables,fail2ban)

System monitoring:
- Netdata, Grafana
- Custom dashboard for cluster/software using Prometheus and node_exporter as "data gathering layer"

System troubleshoot:
- lsof, journactl, find, egrep, for, ps, awk "AS RAINING"
- git + semantic versioning as MUST

Binary exploitation:
- gdb and a lot of memory addresses

Key Skills UNIX, golang, Java, python, block-chain, distributed system, penetration testing, system administration, micro-services, no-SQL, rest-api, optimization, tuning, neural-network, 1984