A magic word that will save you a lot of pain and misery is "STOP". There are some things on a bike that will require both the right tool and force, removing a freewheel there for a long time, bottom bracket again left for a long time and the ubiquitous handlebar stem/saddle post that was last greased a long time ago and "may" have welded itself to the steerer tube or seat tube. But for the rest, and even for these things mentioned, they almost always come apart and go back together again without a great deal of force. So when you aren't able to remove something and are ready to take that long handled steel tool to horse that aluminum part off the bike-"STOP" and really look hard/come ask for advice on the forum. There's usually a reason something is not coming off or going back on easily and penetrating oil and time for it to soak in, new grease, a different tool, etc. will remove/install the part. Going past "STOP" to breakage is a hard teacher.