I like some pretty unusual liqueurs: absinthe, green Chartreuse, St. Germain, etc. This drink helped me find another use for my absinthe. This stuff was fantastic. Strong though, not an every day drink if you like your liver.
2 oz. bourbon
1 oz. fresh squeezed lime juice (There's a pandemic on, man. I used what I had. Didn't make a difference.)
1/2 oz. simple syrup
1/2 oz. grenadine (use the sugary bright red stuff if you want the pretty color - I use my good stuff for the actual drink and it's fantastic, just ugly)
1/4 oz. absinthe
Shake it all together and strain it into a chilled glass.
Absinthe is a favorite of mine, but most people hate it because the absinthe they have had is that bright green, sugary crap. Good liqueurs aren't a dime a dozen and sometimes trying more than one is necessary to find a fit. Many finer cocktail lounges will allow samples if you are nice. Just be nice.
Oh, and by the way, absinthe won't make you see little green men unless there are literally already little green men around you.