Having experienced a windshear encounter just after takeoff, I can
assure you that it is quite hazardous. In my case we both lost 10-15
knots of airspeed and simultaneously were blown a good 200 feet to the
right. I very nearly had to land in the grass. The aircraft was
descending rapidly at full power. I was able to arrest the descent at
perhaps 5-10 feet of altitude, and then gradually regain climbing
flight.

The airport had no windshear warning system.

The tower had warned us of nothing. They seemed quite blase about it
when I reported it, like "Oh, yeah, yawn that's pretty common over
there on that runway."

Trust not the weather prophets for when the truth is not in them they
will not accompany thee amongst thine ancestors.