Do you take any medications? Certain medications like SSRI's, various bipolar & anti-psychotic medications and such can very much reduce/almost completely/completely block a psychedelic from having any effects.
Also did you use a scale? Saying you took 100mg if you just took 1/10th of what you were given as a gram could mean you took 20mg, it could mean you took 300mg, it could mean you took 50mg, it doesn't really say much. Powders have different volumes so 100mg of one powder can look like 20mg of another for example. So whether or not you weighed it with a milligram scale also comes into question.
If you both weighed it and haven't been on any such medications ever then my guess is either your scale was off or the quality/authenticity of your 2C-B is in question. You could have had bk-2C-B for example, in which case your experience would make sense, and there may have been some mix up down the line before you got it. It's also possible your 2C-B degraded somehow by you exposing it to a lot of excess moisture/heat/etc (though phenethylamines are pretty stable so you'd have to do something pretty bad to make it degrade like that).
Another possibility is someone tried to cut the 2C-B to make themselves a little money, cutting something in powder form might make for an even consistency originally but once the bag's been moved around a little it's no longer even and there'll be hotspots where 15mg of powder is 15mg of active substance, and other spots where 150mg of powder only has 10mg of active substance for example.
