I see you have one of my business cards, so surely you noticed the quite large print there indicating "by appointment only." Which of my associates referred you to me? Anansi? Ahriman? Set? Ah, well, I guess I can make an exception; you seem a little desperate for my services, and I can never really turn down a hard case, but don't forget your side of the deal. I don't do this shit pro bono, kapeesh?
I admit I have to get a little more creative about the options on the menu; these days your rivals don't have a convenient herd of kine for me to blight, and not enough people knit for me to use tangled yarn as a common mode of retribution. Still, we have no shortage of technological wonders for me to disrupt, and the sheer abundance of new social conventions is a guarantee that most of them can somehow be made awkward. The postmodern world is a fit place for gods of mischief.
Here are some choice curses to invoke upon your enemies; take your time and make your selections wisely.
The Mild - So you had a shitty day, huh? Sic one of these on someone who makes your blood boil, and see if that doesn't make you feel a little better.
May their shoelaces come untied seconds before walking through a puddle of melted February slush.
May they always need three tries to insert a USB drive.
May their garbage bag always open from the opposite end of the first end they try.
When reading a new e-book, may they accidentally navigate to the second-to-last page through a careless swipe of the touchscreen, causing them to lose their place, and all their devices to sync to the new starting position.
The Moderate - Ah, I see you have a discerning palate! I'm especially fond of this category.
May they get caught reading political threads on reddit, while at work.
May they drop their keys in the grocery store parking lot, and then accidentally kick them underneath their own car, too far to reach without crawling belly-down on the asphalt... and as they do, may there be a pile of something dubious and vile-smelling on the ground where they must crawl to reach their keys.
May their washing machine break just as they are out of quarters for the laundromat, forcing them to visit their mother-in-law to get their clothes cleaned.
May their house cat become overly interested in the process of wrapping Christmas presents.
The Spicy - So we're breaking out the hard stuff, then? Cool, I'm game. Just be aware that at this point, unless they're the kind of jerkass who really deserves it, we're now stepping into "You're the asshole here" territory.
May a nest of cockroaches infest the tower of their PC, producing a mysterious odor when they jam the fan so badly that the PC overheats.
May they mistake Sriracha sauce for ketchup.
May they get caught in an NSFW subreddit at work.
May their primary e-mail account get phished, forcing them to resort to using their embarrassing account from their teenage years... you know, the one that says something like firstname.lastname@example.org.
The Heinous - Wow, buddy, still here? You must be pretty serious about this. Not that I'm one to judge. Me, I like my revenge preemptive, disproportionate, and highly theatrical.
May they butt-dial their ex while attending a musical theatre performance... and when they do, may their unmuted ringtone be The Thong Song by Sisqo.
May their toilet be broken when they return home from eating Taco Bell.
May their backups fail and their password be lost for their cloud storage, the day before a crucial work presentation.
May they step barefoot on a LEGO brick.
Feel free to mix and match these as you please, and do spell my name right on the letter - that's Laguz, Othala, Kaunaz, Isaz - bingo, pal; you got it! Leave the accompanying offering at your nearest vé or other generically mystical-seeming location, and I'll see what I can do for ya'.