Enabling all sensor packs without consideration of implications isn’t good idea. Some of sensors are heavy and may produce overhead. But some of the sensor, especially custom ones needs hot sensor placement for java (agent overview and right click on agent you need, pick hot sensor placement)z .net agents need to be restarted (for example iis recycle, .net service restart).
If your process is custom one (for example .net service) you have to create special sensors called entry points. There are the ones that are starting point for transactions.