Don't use helium for recreational purposes (e.g. balloons). Helium is the second most abundant element in the universe, but here on Earth it is a scarce non-renewable resource that should be used sparingly.
Don't live in a place with a climate you hate. Living in a place with a climate you can't stand can have a high environmental footprint and can cost you a lot of money.
Don't buy or use firecrackers: they are dangerous, wasteful and polluting. When lots of people use firecrackers at the same time (for example during New Year's Eve celebrations) the sudden, very loud sounds they make also cause significant distress to both pets and wild animals.
Don't use the term "soydev" in a derogatory manner to refer to software developers you don't like: there's nothing wrong with consuming soy! In particular, it's certainly much better to consume soy or other legumes rather than meat or other animal products, for a lot of reasons.