“There is a time and a place for everything” (Eccl 3:1). While vacationing, you may have heard a concert pianist playing beautiful music in the lobby of a hotel. That would have been a blessing from God, and appreciation of it is from Him. This is entertainment; not worship. As such, as the song ended, you may have expressed appreciation with hearty applause. It is right to do so.
On the first day of the week, Christians meet with one another to worship God (Heb 10:25). They sing praises to Him as they teach and exhort each other (Eph 5:19; Col 3:16). They pray (I Tim 2:8-9) and present offerings (I Cor 16:1-2). They hear a message from God’s Word (Acts 20:7). They do not applaud or shout approval as to performers; that would not be appropriate in that sacred setting. If they are moved to express agreement, they may say “Amen” (I Cor 14:16). If they wish to express appreciation to the speaker afterward, they tell him afterward. In worship they did not sing “I Left My Heart in San Francisco,” for that would have been out of place. Nor did a pianist play in the hotel lobby, “How Great Thou Art.”
God said there is to be a “distinction between the holy and the common” (Lev 10:10; I Pet 2:5).
Let us make proper distinctions between worship and carnal things.