Ever regret helping someone?

Wow that dude needs to seriously back off. Sorry you had to go through that... hopefully it doesn't happen again u_u I'd just block em without saying anything next time.

Nothing to that extent and probably not even something to complain about... but I usually regret agreeing to go on island tours with people. It sounds like a fun idea at the time but I get so bored of them but I feel bad for wanting to leave after doing like 3 tours.

So sorry that happened to you >.<. Luckily, the ACNL groups I frequent (here and a discord channel) are generally nice, but there's always going to be someone to ruin even just a random act of generosity (avoid club Tortimer at all cost - or just do worldwide. At least there, you can pretend to not know your mother tongue)... That kid is just a leech and lazy. I would have turned the wifi switch off, deleted his FC, and blocked him on social media, the second he asked me to do landscaping without offering some form of payment (IGB, DLC/unorderables or something). It takes a long time to get a town looking just right, getting dreamies, planning PWPs, getting full shops, paying off loans, etc. No one is entitled to shortcuts and should be grateful for any help they receive.

Oh my gosh.. you're such a nice, sweet person. I can't believe that guy took advantage of you like that! That's just way too much and downright crazy.. I'm so sorry this happened to you.
That sort of thing hasn't happened to me yet but I have met someone that is trying to take advantage as well. In my case, it's ok the first time, but it's definitely not happening again.

I'm so sorry you went through that. Unfriend him and block his account. Honestly, if it were me I would've refused the moment he asked me to landscape. People who are not grateful or appreciative for people going out of their way to give them things and help them out aren't worth being helped to begin with.
I would say, stick to here for trading. Belltree has one of the best online communities I've ever been in. Most everyone is extremely kind and polite. And I've only had a few negative experiences.

I've never experienced anything as extreme as your situation, but I have had a guy I traded with once who liked to invite himself over to my town randomly and expect me to hangout with him. Which, I mean I like having people over to my town, but I also like to arrange times. ?\_(ツ)_/?