A good example are the blackberries. They proliferate anyplace there is a disturbance and sometimes seem to have a malevolent intelligence. As you push through them, the branches whip backwards, hitting you in the back of the head and sometimes knocking off your hat. But blackberries are good in that they provide significant food for wildlife and habitat. You can eat them yourself. They taste good but they are small and you have to take a lot of thorns for your meager meal.
The next picture is a devil’s walking stick (Aralia spinosa). It is mostly harmless but it does hurt to run into it. They are very common on our land in Freeman but completely absent on the Brodnax farms a few miles away. I had to cut a couple dozen of them out of my longleaf patch. You have to be very careful. You grab them with you gloved left hand an whack them with a downward stroke from your machete. You need to hold tight, however, because if you hit it loosely, it hits back.
My last picture is a tree of heaven (Ailanthus altissima). This is nothing but trouble with no redeeming characteristics in a rural setting. There are some uses in degraded urban environments, since they grow fast and can grow almost anywhere. They are nearly impossible to eradicate. If you chop them down, they grow back more vigorously. There is no effective method I have ever heard about that does not require chemicals and even with this you cannot win a final victory. I have been spraying these things for years and go after them whenever I see them.
I was indolent with the one in the picture. I noticed the clump in the middle of the wildlife plot last year, but I didn’t have my sprayer with me so I left it. I went back last week. It had growing bigger and thicker and about a dozen little ones had sprouted as far as 100 yards away. I think I got most of them, but I am sure they will be back.