I like airdrop, because very easy registration and coins are free. I participate in many, even if 50% will pay it well. Every day, in my spare time, I watch a new airdrop in the telegram, but I do not take everything. I also learn about new coins.
That last part has been a big one for me. I'll stumble across a cool project here and there because I saw them on an airdrop announcement site. Some of them are smaller communities but have a legit product/project, so seeing them grow is fun.