GA pilot reported being at 2;000 feet and directly in line with the ILS Runway 36 at PIE after departing SPG airport in a Northwest direction. Reportedly; the TPA TRACON Controller had to vector away a distant PIE arrival due to the reporter's aircraft position and told the reporter this was a common occurrence.

Narrative

The event that occurred is as follows: I conducted two touch and go's at SPG before departing to the North West with the intention of staying below the 100/30 Class B airspace and to minimize travel time by cutting close to PIE Class D airspace. As I departed SPG airspace I was given the Tampa Approach frequency by the SPG Controller. I maintained 2;000 feet and outside of PIE; however; my route placed my aircraft directly inline with the ILS for Runway 36 at PIE. The Controller at Tampa asked if I was on frequency after vectoring the 'distant' incoming traffic to PIE because of me. I immediately responded with a yes. He proceeded to verbally tell me that I was in the way and asked me for my intentions. I responded that I was returning to ZZZ. The Controller cleared me into the Class B airspace and asked me to provide a desired altitude. I asked for ceilings and the Controller asked other aircraft for ceilings. Eventually I requested for 5;500 feet and was approved to climb. Later; when traffic lightened; the Controller advised me of my legal but disruptive intrusion of the ILS for Runway 36 at PIE. He proceeded to inform me that this is a common occurrence and everything was okay; but to just make me aware of the situation to prevent it from happening again.I did not fully brief myself of the surrounding area enough to understand that even though I was not violating airspace; I was being very rude and ignorant to surrounding traffic.